Name given to a long drawn-out dispute in the early Church over the exact date for the celebration of Easter. The dispute originated between the West and East, about the middle of the 2nd century, over the practise followed in the Eastern Church of terminating the Lenten Fast and beginning the Easter celebration on the 14th day of the Jewish month, Nisan, regardless of the day on which this date might fall. This was the day on which the Jews celebrated the Passover, and hence, as the Easterners maintained, the day on which Christ had kept the Pasch and instituted the Blessed Eucharist. Therefore, to their way of thinking, since the two great festivals, Hebrew and Christian, stood to one another in the relation of type and reality, it was only fitting that the Christian Pasch be celebrated on the same day. Although they claimed to have received this practise from the Apostles, John and Philip, they were called by the Westerners “Quartodecimans” (quartus decimus, fourteenth) and “Observants,” since, while they did not keep the festival of the Jewish Pasch, still they “observed” the day.
The Western Church, on the other hand, always celebrated the Christian Pasch on the Sunday following the 14th day of the full moon of the vernal equinox, because that day was regarded as the exact date on which Christ arose from the dead, finished the work of redemption and accomplished our deliverance from the Egyptian bondage of death and hell. In support of this practise the Westerners appealed to the authority of Saint Peter and Saint Paul. Discussion waxed hot and a schism was probably averted through the energetic, if somewhat harsh measures of Pope Victor I, who terminated the quartodeciman controversy by threatening with excommunication all those who failed to comply with the Roman custom. The East accordingly adopted the Sunday celebration. The Church of Antioch, however, instead of computing this Sunday as the first after the 14th day of the full moon of the vernal equinox, began to compute it as the first after the 14th day of Nisan. This made a difference, and gave a new turn to the controversy. The Christians of Rome and Alexandria charged that the Jews had adopted very arbitrary methods in determining their year and had become neglectful of the law that the 14th of Nisan must never precede the equinox. The charge seems to have been well-founded, as discrepancies soon appeared between the Easter celebration at Antioch and in the rest of the Christian world.
The General Council of Nice in 325 paved the way to a final settlement of the difficulty by ruling: that Easter must be celebrated by all throughout the world on the same Sunday; that this Sunday must follow the 14th day of the paschal moon; that that moon was to be accounted the paschal moon whose 14th day followed the spring equinox; and that some provisions should be made for determining the proper date of Easter and communicating it to the universal Church. Long after the Roman Church had adopted the cycle of 95 years for determining the date of Easter, the Celtic Church still followed a cycle of 532 years and celebrated the feast on a Sunday differing from the rest of Christendom. By the 9th century the Easter question was settled in all parts of the Celtic Church, and the cycle of 95 years followed everywhere.