Quartodecimanism

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).