44. The nineteen-year cycle
[IV. THE PASCHAL TABLE (CHS. 44^65)]
44. THE NINETEEN-YEAR CYCLE
Eusebius,bishopofCaesareainPalestine,¢rstdevisedthesequenceofthe 19-year cycle in order to ¢nd the fourteenth Moons of the Paschal feast and the day of Easter itself, because after this period of time a Moon of a given age will recur on the same day of the solar year.1 Not that hitherto the Egyptian or other Churches of Christ in the East did not know how to ¢nd the course of the Moon or the day of Easter in the correct way, but because these matters, which at that time used to be determined year by year, with much di⁄culty, and then promulgated throughout the world ^
[whence] arose many queries ^ could [now], by being readily established in advance according to a cyclical principle, be observed in perpetuity and learned by heart without anxiety about disputes.2
Therefore it is claimed that from time immemorial it was delegated to the Church of Alexandria, by way of obligation, to take upon itself the task and duty of investigating /419/ the Paschal computation, so that when it announced [the same] to the Ponti¡ of the Apostolic See, the rulers of the churches might be informed through him of the date of Easter. Hence the blessed Pope Leo, when he asked the Emperor
Marcian to refer to the bishop of Alexandria the conduct of a careful investigation of the Easter [cycle] of St Theophilus,3 in which it appears that the 8th kalends of May [24 April] is assigned to Easter Day, gave his judgement that the aforementioned day had not correctly been chosen by [Theophilus]. Amongst other things, he says: Some of the holy
Fathers sought an opportunity to remove this error, delegating this entire responsibility to the bishop of Alexandria, for it seemed that skill in this calendrical computation had been handed down from of old amongst the Egyptians, and for many years the day of the aforementioned celebration would be indicated by [the bishop] to the Apostolic See, by whose writ a 1 Jerome, De viris illustribus 61, ed. W. Herding (Leipzig: Teubner, 1879):41.28^
42.3; cf. Isidore, Etym. 6.17.
2 Cf. Bede, HE 5.21 (544^546).
3 I.e. the 19-year cycle.