Квартидециманы: Празднование Пасхи 14 нисана.

Observing the Easter on the eve of 14 Nisan
Quartodecimanism (from the Vulgate Latin quarta decima in Leviticus 23:5, meaning fourteenth) is the name given to the practice of celebrating the death of Christ on the day of Passover, the 14th of Nisan according to biblical dating, on whatever day of the week it occurs. The Quartodeciman controversy in the Church was the question of whether to celebrate Easter on Sunday (the first day of the week), or on Passover (the time of sacrifice of the Passover lamb).

[[File:Saint Polycarp. Engraving. Wellcome V0032929. jpg|thumb|Saint Polycarp was a Quartodeciman. The Quartodecimans claimed that their traditions are inherited from the Apostles John and Philip, while western churches claimed that their views of Easter have been inherited from Paul and Peter. Quartodecimanism was popular in Asia Minor, Jerusalem and Syria, however it was rejected by churches in other regions. Polycarp, like other Asiatics, kept Easter on the fourteenth day of the month of Nisan. According to Eusebius, Polycarp claimed that his practice came from the apostle John. Some of the Montanists were also Quartodeciman. Montanism brought Quartodeciman practices to the west, for example Blastus was a Roman Montanist who was also a Quartodeciman. It is unclear if the Ebionites were Quartodeciman, however they probably observed Passover in addition to other Jewish festivals. The Didascalia likely drew from a Quartodeciman source. Some Novatians that spread into the east were Quartodecimans. By the 4th century the influence of Quartodecimans declined; later they would even be persecuted. The opponents of Quartodecimanism argued that it is a form of Judaizing.

The Quartodeciman controversy arose because Christians in Jerusalem and Asia Minor observed Easter on the 14th of the first month (Nisan), regardless of the day of the week on which it occurred, while the churches in and around Rome celebrated Easter on the Sunday following first Full Moon following the vernal equinox, calling it "the day of the resurrection of our Saviour". The difference became an ecclesiastical controversy when the practice was condemned by synods of bishops.