Корей жосанының негізін қалаушы Тэйджо

Founding king of Joseon from 1392 to 1398

Taejo (hangul=태조; 4 November 1335 – 27 June 1408), personal name Yi Sŏng gye (hangul=이성계), later Yi Tan (hangul=이단), was the founder and first monarch of the Joseon dynasty of Korea. After overthrowing the Goryeo dynasty, he ascended to the throne in 1392 and abdicated six years later during a strife between his sons. He was honored as Emperor Go (hangul=고황제) following the establishment of the Korean Empire. Taejo emphasized continuity over change. No new institutions were created, and no massive purges occurred during his reign. His new dynasty was largely dominated by the same ruling families and officials that had served the previous regime. He re established amicable ties with Japan and improved relations with Ming China.

Taejo's father was Yi Cha ch'un, an official of Korean ethnicity serving the Mongol led Yuan dynasty. His mother, Lady Ch'oe, came from a family originally from Deungju (present day Anbyŏn County, North Korea).

By the late 14th century, the 400 year old Goryeo dynasty established by Wang Geon in 918 was tottering, its foundations collapsing from years of war and de facto occupation by the disintegrating Mongol Empire. The legitimacy of the royal family itself was also becoming an increasingly disputed issue within the court, as the ruling house not only failed to govern the kingdom effectively, but was also affected by rivalry among its various branches and by generations of forced intermarriage with members of the Yuan imperial family, while King U's biological mother being a known slave led to rumors contesting his descent from King Gongmin. Influential aristocrats, generals, and ministers struggled for royal favor and vied for domination of the court, resulting in deep divisions between various factions. With the ever increasing number of raids against Goryeo conducted by Japanese pirates and the Red Turbans, those who came to dominate the royal court were the reformed minded Sinjin faction of the scholar officials and the opposing Gwonmun faction of the old aristocratic families, as well as generals who could actually fight off the foreign threats—namely Yi Sŏng gye and his rival Ch'oe Yŏng. As the Ming dynasty started to emerge, the Yuan forces became more vulnerable, and Goryeo regained its full independence by the mid 1350s, although Yuan remnants effectively occupied northeastern territories with large garrisons of troops.

Yi Sŏng gye started his career as a military officer in 1360, and would eventually rise up the ranks. General Yi had gained prestige during the late 1370s and early 1380s by pushing Mongol remains off the peninsula and also by repelling the well organized Japanese pirates in a series of successful engagements. In 1393, he changed his dynasty's name to Joseon. Among his early achievements was the improvement of relations with the Ming; this had its origin in Taejo's refusal to attack their neighbor in response to raids from Chinese bandits. Envoys were also dispatched to Japan, seeking the re establishment of amicable connections. The mission was successful, and Shōgun Ashikaga Yoshimitsu was reported to have been favorably impressed by this embassy. When the new dynasty was officially promulgated, the issue of which son would be the heir to the throne was brought up. Although Yi Pang wŏn, Taejo's fifth son by his first wife Queen Sinui, had contributed the most to his father's rise to power, he harbored a profound hatred against two of Taejo's key allies, Jeong Do jeon and Nam Ŭn. Both sides were fully aware of the mutual animosity and felt constantly threatened. When it became clear that Yi Pang wŏn was the most worthy successor, Jeong Do jeon used his influence to convince the king that the wisest choice would be the son that he loved most, not the son that he felt was best for the kingdom. In 1392, the eighth son of King Taejo (his second son by Queen Sindeok), Yi Pang sŏk, was appointed as crown prince. After the sudden death of the queen in 1396 and while Taejo was still in mourning for his wife, Jeong Do jeon began conspiring to pre emptively kill Yi Pang wŏn and his brothers to secure his position in the royal court. In 1398, upon hearing of this plan, Yi Pang wŏn immediately revolted and raided the palace, killing Jeong Do jeon, his followers, and the two sons of the late Queen Sindeok. This incident became known as the 'First Strife of Princes' (hangul=제1차 왕자의 난). Aghast at the fact that his sons were willing to kill each other for the throne and psychologically exhausted by the death of his second wife, Taejo immediately named his second son, Yi Pang gwa (posthumously King Jeongjong), as the new successor and abdicated. Thereafter, Taejo retired to the Hamhung Royal Villa and maintained distance with his fifth son for the rest of his life. Allegedly, Yi Pang wŏn sent emissaries numerous times, and each time the former king executed them to express his firm decision not to meet his son again. This historical anecdote gave birth to the term Hamhung Chasa (hangul=함흥차사), which means a person who never comes back despite several nudges. However, recent studies have found that Taejo did not actually execute any of the emissaries; these people died during revolts which coincidentally occurred in the region. In 1400, King Jeongjong pronounced his younger brother Yi Pang wŏn as heir presumptive and voluntarily abdicated. That same year, Yi Pang wŏn assumed the throne of Joseon at last; he is posthumously known as King Taejong.

King Taejo died ten years after his abdication, on June 27, 1408, in Changdeok Palace. He was buried at Geonwonneung (hangul=건원릉), Dongguneung Cluster, in present day Guri, Gyeonggi Province, South Korea. The tomb of his umbilical cord is located in Geumsan County, South Chungcheong Province, also in South Korea.

Although Taejo overthrew Goryeo and expelled officials who remained loyal to the previous dynasty, many regard him as a revolutionary and a decisive ruler who eliminated an inept, obsolete and crippled governing system to save the nation from foreign forces and conflicts. The resulting safeguarding of domestic security led the Koreans to rebuild and further discover their culture. In the midst of the rival Yuan and Ming dynasties, Joseon encouraged the development of national identity which was once threatened by the Mongols. However, some scholars, particularly in North Korea, view Taejo as a mere traitor to the old regime and bourgeois apostate, while paralleling him to General Ch'oe Yŏng, a military elite who conservatively served Goryeo to death. His diplomatic successes in securing Korea in the early modern period are notable.

One of the many issues demonstrating the early strained relationship between Joseon and Ming was the debate of Taejo's genealogy, which began as early as 1394 and became a sort of diplomatic friction that lasted over 200 years. The Collected Regulations of the Great Ming erroneously recorded 'Yi Tan' (Taejo's personal name) as the son of Yi In im, and that Yi Tan killed the last four kings of Goryeo, thereby establishing Ming's opinion of Taejo as an usurper first and foremost, from the time of the Hongwu Emperor when he repeatedly refused to acknowledge him as the new sovereign of the Korean Peninsula. The first mention of this error was in 1518 (about 9 years after the publication), and those who saw the publication made petitions towards Ming demanding for redress, among others left chanseong Yi Kye maeng and minister of rites Nam Gon, who wrote Jonggye Byeonmu (hangul=종계변무). It took until 1584 (after many Ming envoys had seen the petitions), through chief scholar Hwang Chŏng uk, that the issue was finally addressed. The Wanli Emperor commissioned a second edition in 1576 (covering the years between 1479 and 1584). About a year after its completion, Yu Hong saw the revision, and returned to Joseon with the good news.

Portrayed by Im Dong jin in the 1983 KBS TV series Foundation of the Kingdom. Portrayed by Kim Mu saeng in the 1983 MBC TV series The King of Chudong Palace and in the 1996 KBS TV series Tears of the Dragon. Portrayed by Lee Jin woo in the 2005–2006 MBC TV series Shin Don. Portrayed by Oh Jae moo in the 2012 SBS TV series Faith. Portrayed by Ji Jin hee in the 2012–2013 SBS TV series The Great Seer. Portrayed by Yoo Dong geun in the 2014 KBS1 TV series Jeong Do jeon. Portrayed by Lee Dae yeon in the 2014 film The Pirates. Portrayed by Lee Do kyung in the 2015 JTBC TV series More Than a Maid. Portrayed by Son Byong ho in the 2015 film Empire of Lust. Portrayed by Chun Ho jin in the 2015–2016 SBS TV series Six Flying Dragons. Portrayed by Kim Ki hyeon in the 2016 KBS1 TV series Jang Yeong sil. Portrayed by Lim Jong yun in the 2016 film Seondal: The Man Who Sells the River. Portrayed by Kim Yeong cheol in the 2019 JTBC TV series My Country: The New Age and 2021 KBS1 TV series The King of Tears, Lee Bang won. Portrayed in the mobile/PC game Rise of Kingdoms.