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This is a list of calendars. Included are historical calendars as well as proposed ones. Historical calendars are often grouped into larger categories by cultural sphere or historical period; thus O'Neil (1976) distinguishes the groupings Egyptian calendars (Ancient Egypt), Babylonian calendars (Ancient Mesopotamia), Indian calendars (Hindu and Buddhist traditions of the Indian subcontinent), Chinese calendars and Mesoamerican calendars. These are not specific calendars but series of historical calendars undergoing reforms or regional diversification. In Classical Antiquity, the Hellenic calendars inspired the Roman calendar, including the solar Julian calendar introduced in 45 BC. Many modern calendar proposals, including the Gregorian calendar introduced in 1582 AD, contains modifications from that of the Julian calendar.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

In the list below, specific calendars are given, listed by calendar type (solar, lunisolar or lunar), time of introduction (if known), and the context of use and cultural or historical grouping (if applicable). Where appropriate, the regional or historical group (Jewish calendar, Hijri calendar, Sikh, Mayan, Aztecan, Egyptian, Mesopotamian, Iranian, Hindu, Buddhist, Pre Columbian Mesoamerican, Hellenic, Julian or Gregorian derived) is noted. Calendars fall into four types: lunisolar, solar, lunar and seasonal. Most pre modern calendars are lunisolar. The seasonal calendars rely on changes in the environment (e. g., "wet season", "dry season") rather than lunar or solar observations. The Islamic and some Buddhist calendars are lunar, while most modern calendars are solar, based on either the Julian or the Gregorian calendars. Some calendars listed are identical to the Gregorian calendar except for substituting regional month names or using a different calendar epoch. For example, the Thai solar calendar (introduced 1888) is the Gregorian calendar using a different epoch (543 BC) and different names for the Gregorian months (Thai names based on the signs of the zodiac). Name Type Group Introduction Usage Comments Hebrew/Jewish Calendar lunisolar Canaan/Mesopotamian Circa 3761 BC Western World It is based on lunar months with the intercalation of an additional month every 2 to 3 years to bring the cycle closer to the solar cycle. It is used to determine the dates for Jewish holidays and the appropriate public reading of Torah portions, yahrzeits (dates that commemorate the death of a relative), daily Psalm readings, and many other holidays, festivals and ceremonial uses. Egyptian calendar fixed (365 days) Egyptian Bronze Age Middle Kingdom The year is based on the heliacal rising of Sirius (Sothis) and divided into the three seasons of akhet (Inundation), peret (Growth) and shemu (Harvest). The heliacal rising of Sothis returned to the same point in the calendar every 1,460 years (a period called the Sothic cycle). Umma calendar lunisolar Mesopotamian Bronze Age Sumer/Mesopotamia Recorded in Neo Sumerian records (21st century BC), presumably based on older (Ur III) sources. Pentecontad calendar solar Mesopotamian Bronze Age Amorites A Bronze Age calendar in which the year is divided into seven periods of fifty days, with an annual supplement of fifteen or sixteen days for synchronisation with the solar year. Four Seasons and Eight Nodes solar Chinese Bronze Age(?) China The years is divided into four seasons, and each season is divided into a festival and three months. The start and middle of each season is the key node of the year. Gezer Calendar unknown Mesopotamian 1000 BC Israel/Canaan The years are divided into monthly or bi monthly periods and attributes to each a duty such as harvest, planting, or tending specific crops. Roman calendar lunisolar Roman 713 BC Roman Republic Based on the reforms introduced by Numa Pompilius in c. 713 BC. Six Ancient Calendars lunisolar Chinese Iron Age China Six classical (Zhou era) calendars: Huangdi, Zhuanxu, Xia, Yin, Zhou's calendar and Lu. Nisg̱a'a seasonal / lunisolar Indigenous North America Nisg̱a'a The Nisga’a calendar revolves around harvesting of foods and goods used. The original year followed the various moons throughout the year. Inuit seasonal Indigenous North America Inuit The Inuit calendar is based on between six and eight seasons as solar and lunar timekeeping methods do not work in the polar regions. Haab' fixed (365 days) Pre Columbian (Maya) 1st millennium BC Maya Tzolk'in fixed (260 days) Pre Columbian (Maya) 1st millennium BC Maya Xiuhpohualli fixed (365 days) Pre Columbian (Aztec) Aztecs Tonalpohualli fixed (260 days) Pre Columbian (Aztec) Aztecs Attic calendar lunisolar (354/384 days) Hellenic 6th century BC Classical Athens The year begins with the new moon after the summer solstice. It was introduced by the astronomer Meton in 432 BC. Reconstructed by Academy of Episteme. Old Persian calendar lunisolar(?) Iranian 4th century BC(?) Persian Empire Based on earlier Babylonian/Mesopotamian models Seleucid calendar lunisolar Hellenic/Babylonian 4th century BC Seleucid Empire Combination of the Babylonian calendar, ancient Macedonian (Hellenic) month names and the Seleucid era. Genesis Calendar lunisolar Chinese Han dynasty China Introduced the "month without mid climate is intercalary" rule; based on a solar year of 365385/1539 days and a lunar month of 2943/81 days (19 years=235 months=693961/81 days). Ptolemaic calendar solar Egyptian 238 BC Ptolemaic Egypt The Canopic reform of 238 BC introduced the leap year every fourth year later adopted in the Julian calendar. The reform eventually went into effect with the introduction of the "Alexandrian calendar" (or Julian calendar) by Augustus in 26/25 BC, which included a 6th epagomenal day for the first time in 22 BC. Julian calendar solar Roman 45 BC Western World Revision of the Roman Republican calendar, in use in the Roman Empire and the Christian Middle Ages, and remains in use as liturgical calendar of Eastern Orthodox Churches. Kurdish calendar solar Kurdish Kurdistan Kurdistan Region is a calendar used in the Kurdistan region of Iraq alongside the Islamic and Gregorian calendar. The First day in this month is called "Newroz" it means "New Day". The start of the calendar is marked by the Battle of Nineveh, a conquest of the Assyrians by the Medes and the Babylonians in 612 BC. Coptic calendar solar Egyptian 1st century Coptic Orthodox Church Based on both the Ptolemaic calendar and the Julian calendar Ge'ez calendar solar Ethiopian 1st century Ethiopia, Ethiopian Christians, Eritrea, Eritrean Christians the calendar associated with Ethiopian and Eritrean Churchs, based on the Coptic calendar Berber calendar solar Julian In Roman times North Africa Julian calendar used for agricultural work. Qumran calendrical texts fixed (364 days) — c. 1st century Second Temple Judaism Description of a division of the year into 364 days, also mentioned in the pseudepigraphical Book of Enoch (the "Enoch calendar"). Coligny calendar lunisolar Gauls/Celts Iron Age Gauls/Celts Early calendar used by Celtic peoples prior to the introduction of the Julian calendar, on a bronze plaque c. AD 200 but likely some centuries older. Zoroastrian calendar fixed (365 days) Iranian 3rd century Sassanid Persia Based on both the Old Persian and Seleucid (Hellenic) calendars. Introduced in AD 226, reformed in AD 272, and again several times in the 5th to 7th centuries. Chinese Calendar, Dàmíng origin lunisolar Chinese 510 China Created by Zu Chongzhi, most accurate calendar in the world at its invention Japanese calendar lunisolar Chinese derived 6th century Japan Umbrella term for calendars historically and currently used in Japan, in the 6th century derived from the Chinese calendar Chinese Calendar, Wùyín origin lunisolar Chinese 619 China First Chinese calendar to use the true moon motion Islamic calendar (Lunar Hijri calendar) lunar Muslim 632 Islam Based on the observational lunisolar calendars used in Pre Islamic Arabia. Remains in use for religious purposes in most of the Islamic world. Pyu calendar lunisolar Hindu/Buddhist derived 640 mainland Southeast Asia Traditional calendar of Southeast Asia, in use until the 19th century. Traditionally said to originate in 640 (the calendar era) in Sri Ksetra Kingdom, one of the Burmese Pyu city states. Byzantine calendar solar Julian 988 Ecumenical Patriarchate of Constantinople Julian calendar with Anno Mundi era in use c. 691 to 1728. Armenian calendar fixed (365 days) Iranian medieval medieval Armenia Calendar used in medieval Armenia and as liturgical calendar of the Armenian Apostolic Church. Derived from the Zoroastrian (or related medieval Iranian calendars such as the Sogdian/Choresmian ones). It uses the era AD 552. In modern Armenian nationalism, an alternative era of 2492 BC is sometimes used. Bulgar calendar solar Bulgarian Bronze Age Volga Bulgaria A reconstruction based on a short 15th century transcript in Church Slavonic called Nominalia of the Bulgarian Khans, which contains 10 pairs of calendar terms. Florentine calendar solar Julian Medieval Republic of Florence Variant of the Julian calendar in use in medieval Florence Pisan calendar solar Julian Medieval Republic of Pisa Variant of the Julian calendar in use in medieval Pisa Tamil calendar solar Hindu Ancient Tamil Nadu The Hindu calendar used in Tamil Nadu Kollam Era sidereal solar Hindu825 Kerala It is believed that the era was started by the Syrian Christian saints Mar Sabor and Mar Proth who arrived in Kollam in the 9th century CE. This event is recorded in the Kollam Tarisappalli copper plates issued to them. The news of the physical disappearance of Sri Adi Shankaracharya in 820 CE at Kedarnath reached the Malabar coast only a few years later. It is believed that Kerala began the Malayalam era in 825 CE in his memory. According to Hermann Gundert, Kollam era started as part of erecting a new Shiva Temple in Kollam and because of the strictly local and religious background, the other regions did not follow this system at first. Once Kollam port emerged as an important trade center, however, the other principalities also started following the new system of calendar. This theory backs the remarks of Ibn Battuta as well. The Kollam era may also be attributed to the legend of Paraśurāma, an incarnation of Vishnu. It is sometimes divided into cycles of 1,000 years reckoned from 1176 BCE. Thus, 825 CE would have been the first year of the era's third millennium. Nepali calendar solar Hindu/ Buddhist Medieval Nepal One of the Hindu calendars Nepal Sambat lunisolar Buddhist/ Hindu 9th century Nepal A lunisolar Buddhist calendar traditional to Nepal, recognition in Nepal in 2008. Bengali calendar lunisolar Bengali Medieval Bengal Revised in 1987. Thai lunar calendar lunisolar Hindu/Buddhist Medieval Thailand A Buddhist calendar Pawukon calendar fixed (210 days) Hindu Bali Old Icelandic calendar solar 10th century medieval Iceland Partly inspired by the Julian calendar and partly by older Germanic calendar traditions. Leap week calendar based on a year of 364 days. Vietnamese calendar lunisolar Chinese derived 10th century Vietnam After Vietnam regained independence following the third Chinese domination of Vietnam, the following dynasties established their own calendars based on Chinese prototypes, and every subsequent dynasty had appointed officers to man and create the calendar to be used in the realm. Jalali calendar solar Iranian 1079 Seljuk Sultanate A calendar reform commissioned by Sultan Jalal al Din Malik Shah I Hebrew calendar lunisolar Babylonian/Seleucid derived 11th/12th century Judaism Recorded by Maimonides in the Mishneh Torah, resulting from various reforms and traditions developing since Late Antiquity. The Anno Mundi era gradually replaced the Seleucid era in Rabbinical literature in the 11th century. Tibetan calendar lunisolar Buddhist/Chinese derived 13th century Tibet The Kalacakra, a Buddhist calendar introduced in 13th century Tibet Seasonal Instruction solar Chinese 1281 China Based on a solar year of 365.2425 (equal to the Gregorian year) Runic calendar solar Julian 13th century Sweden A written representation of the Metonic cycle used in medieval and early modern Sweden, allowing to calculate the dates of the full moons relative to the Julian date. The introduction of the Gregorian calendar in Sweden in 1753 rendered the runic calendars unusable. Six Imperial Calendars (ß) solar Chinese Ming dynasty China In use 1368 1644 Incan calendar lunisolar Pre Columbian 15th century Inca Empire Muisca calendar lunisolar Pre Columbian 15th century Muisca Complex lunisolar calendar with three different years, composed of months divided into thirty days. After the Spanish conquest of the Muisca Confederation in present day central Colombia in 1537 first replaced by the European Julian and as of 1582 the Gregorian calendar. Chula Sakarat lunisolar Burmese 16th century Southeast Asia Gregorian calendar solar Julian derived 1582 worldwide Introduced as a reform of the Julian calendar in the Roman Catholic church, since the 20th century in de facto use worldwide. Javanese calendar lunar Islamic influenced 1633 Java Based on the Hindu calendar using the Saka era (78 CE), but changed by Sultan Agung of Mataram its method of counting of years from solar years to lunar years as per the Islamic calendar. Seasonal Constitution solar Chinese 1645 China First Chinese Calendar to use the true motion of the sun. Swedish calendar solar Julian derived 1700 Sweden Part of the controversy surrounding the adoption of the Gregorian calendar, in use 1700–1712. Astronomical year numbering solar Julian derived 1740 Astronomy A mixture of Julian and Gregorian calendar, giving dates before 1582 in the Julian calendar, and dates after 1582 in the Gregorian calendar, counting 1 BC as year zero, and negative year numbers for 2 BC and earlier. French Republican Calendar solar Gregorian 1793 First French Republic In use in revolutionary France 1793 to 1805. Pancronometer solar Gregorian 1745 — Universal Georgian Calendar proposed by Hugh Jones Rumi calendar solar Julian 1839 Ottoman Empire Julian calendar using the Hijri era introduced in the Ottoman Empire. Positivist calendar Solar Gregorian 1849 — Solar calendar with 13 months of 28 days. Badí‘ calendar solar Baháʼí 1873 Baháʼí Uses a year of 19 months of 19 days each and a 1844 era. Also known as the "Baháʼí Calendar" or the "Wondrous Calendar". Thai solar calendar solar Gregorian 1888 Thailand The Gregorian calendar but using the Buddhist Era (543 BC) Invariable Calendar solar Gregorian 1900 — Gregorian calendar with four 91 day quarters of 13 weeks International Fixed Calendar solar Gregorian 1902 — A "perpetual calendar" with a year of 13 months of 28 days each. Minguo calendar solar Gregorian 1912 Republic of China Months and days use the Gregorian calendar, introduced in China in 1912. Revised Julian calendar solar Julian derived 1923 some Orthodox churches currently synchronized with the Gregorian calendar, but different leap rule and cycle (900 years), also called Meletian calendar or Milanković calendar, after Serbian scientist Milutin Milanković who developed it. Solar Hijri calendar solar Iranian/Islamic 1925 Iran, Afghanistan New Year is the day of the astronomical vernal equinox. The calendar as introduced in 1925 revived Iranian month names but counted the years of the Hijri era. The era was changed in 1976 to 559 BC (reign of Cyrus the Great), but was reverted to the Hijri era after the Iranian Revolution. Era Fascista solar Gregorian 1926 Italy Epoch is 29 October 1922; in use from 1926–1943 Soviet calendar solar Gregorian 1929 Soviet Union Gregorian calendar with 5 and 6 day weeks, used during 1929 to 1940. World Calendar solar Gregorian 1930 — Perpetual calendar with 1–2 off week days, preferred and almost adopted by the United Nations in 1950s Pax Calendar solar Gregorian 1930 — Leap week calendar Pataphysical calendar solar Gregorian 1949 — Absurdist variant of the Gregorian calendar by Alfred Jarry. Indian national calendar solar Gregorian derived 1957 Republic of India Gregorian calendar with months based in traditional Hindu calendars and numbering years based on the Saka era (AD 78). Assyrian calendar solar Babylonian 1950s Assyrianism Solar calendar with an "Assyrian era" of 4750 BC, introduced in Assyrian nationalism in the 1950s Discordian calendar solar Gregorian 1963 Discordianism Calendar invented in the context of the absurdist or parody religion of Discordianism, Gregorian calendar variant with a year consisting of five 73 day seasons. World Season Calendar solar Gregorian 1973 — Divides the year into four seasons. Dreamspell solar Mayan 1990 esotericism 13 months of 28 days each, synchronized with the Maya 260 day Tzolkin, calibrated to the Chilam Balam timing systems Tranquility Calendar solar Gregorian 1989 — Modification of the International Fixed Calendar, starting with Apollo 11 Moon landing on 20 July 1969 Holocene calendar solar Gregorian 1993 — The Gregorian calendar with the era shifted by 10,000 years. Juche era calendar solar Gregorian 1997 North Korea Gregorian calendar with the era 1912 (birth of Kim Il sung) Nanakshahi calendar solar Sikh 1789 Sikhism religion, Punjab Sikh Calendar numbering years based on the era 1469 (birth of Guru Nanak) Symmetry454 solar Gregorian 2004 — Leap week calendar with 4:5:4 weeks per month Hanke–Henry Permanent Calendar solar Gregorian 2004 — Leap week calendar with 30:30:31 days per month, revised in 2011 and 2016Igbo calendar solar Indigenous West African 2009 Igbo people Proposal based in Igbo tradition dating back to 13th century, 13 lunar months of 28 days divided into seven 4 day periods, plus leap days. Vikram samwat Lunisolar Hindu Ancient India India/Nepal The Vira Nirvana Samvat (era) is a calendar era beginning on 7 October 527 BCE. It commemorates the Nirvana of Lord Mahaviraswami, the 24th Jain Tirthankara. This is one of the oldest system of chronological reckoning which is still used in India.

Tradition week length commentsBali various Igbo 4 days The traditional Igbo week consists of four market days: eke, orie, afor, and nkwo. Yoruba 4 days Traditional Yoruba calendarKorea 5 days For traditional markets in Korea, for example, the market is open every five days. Java (Pasaran) 5 days Discordian 5 days Akan 6 days A traditional "six day week" which combined with the Gregorian seven day week gave rise to a 42 day cycle. Ancient Rome 8 days The Roman nundinal cycle. Burmese 8 days Celtic 8 days reconstructed. Baltic 9 days Linguistic reconstruction; the Gediminas Sceptre indicated that a week lasted for nine days during King Gediminas' reign. Chinese 10 days Egyptian Calendar 10 days The 10 day period was known as decans or decadesFrench Republican Calendar 10 days Aztecs 13 days Trecena, division of the Tonalpohualli 260 day period