The purpose of observing Easter‘on one day throughout the whole world’is
purportedly only that the devotion of Easter be not disrupted by‘divisions and
dissensions’. Unity of the Church is thus not presented as a rationale or an end
in itself, at least explicitly; but reference to Jesus as‘one person who died for
all’may imply a need for the Church to emulate his unity.^95
For whatever reason, the resolution of the Council of Arles is not known to
have been effectively enforced (Grumel 1960: 169, Lejbowicz 2006: 30); far
more important, in the long term, was the Council of Nicaea in 325CE, which
Constantine convened soon after his conquest of the eastern half of the Roman
Empire, and which brought together Church leaders this time from both East
andWest. The date of Easter was again at the top of the Council’s agenda, on a
par with the question of the Arian heresy—at least according to Eusebius’
account in hisLife of Constantine, which constitutes in this context our main
historical source. The Canons of this Council, in contrast, do not record
anything about the date of Easter; this omission has been rightly explained
as reflecting the fact—implicit also, on close reading, in Eusebius’account
itself—that for reasons to be later explained, no formal or precise decision was
taken at Nicaea about the date of Easter.^96 But this did not prevent Constan-
tine from writing after the Council, in a letter to the churches that is cited by
Eusebius, the general points of principle about the date of Easter which he
believed, or wanted others to believe, had been unanimously agreed. These
points of principle were to develop, in the course of the fourth century, into
precisely defined calendrical rules, and were thus highly influential on the
subsequent history of the date of Easter.
In essence, two resolutions—both rather general and vague—are laid down
in Constantine’s letter: that Easter be celebrated on the same date by all
Christians, and that Christians no longer follow the Jews. I shall examine
each of these resolutions in turn, although in conclusion it will emerge that
they constituted together a single argument. Thefirst resolution, that Easter be
celebrated on the same date, is similar to thefirst canon of Arles, but with
significant differences. On the one hand, the resolution is given a far more
developed rationale, in which the unity of the Church becomes the explicit and
paramount concern. On the other hand, no explanation is given as to how this
universal date of Easter will be determined and proclaimed, and understand-
ably so: for at Nicaea, there was no central episcopal authority (such as the
(^95) Note also that explicit reference is made to theecclesia catholica(universal church) in the
opening of the synodal letter (Gaudemet 1977: 40–1).
(^96) Duchesne (1880), Daunoy (1925), Jones (1943) 17–20, and above all Lejbowicz (2006)
30 – 63, who demonstrates that the common view (often reiterated, erroneously, in history text-
books) that the Council of Nicaea agreed to observe the rule of the equinox and the Alexandrian
19-year cycle represents a late-4th-c. reinterpretation of the events by Church leaders, starting
from Ambrose in 386CE, who were seeking to legitimize the Alexandrian cycle, and on whom see
also Lejbowicz (2008) = (2010).
Sectarianism andHeresy 397