Compromise between Alexandria and Rome remained a policy through
most of the fourth century, but after the death of Athanasius in 373, for
historical reasons that have been explored by others elsewhere, it is Rome
that increasingly conceded to the Alexandrian cycle and its Easter limits.^138
Eventually, in the mid-fifth century, the Alexandrian 19-year cycle was offi-
cially adopted by the Church of Rome.^139 It may thus be said that the Council
of Nicaea, with Constantine’s directive that all Christians observe Easter on
the same date, had the progressive and long-term effect of bringing into
existence a single,‘orthodox’computation for the date of Easter.
Factionalism after Nicaea: the beginnings of calendar heresyBesides uniting various churches in the observance of a common date of
Easter, the Council of Nicaea had the paradoxical counter-effect of enhancing
divisions regarding Easter between dissenting factions. This was only because
the date of Easter had been made at Nicaea a matter of social and doctrinal
significance. From Nicaea onwards, the observance of different Easter dates
could no longer be dismissed as a matter of regional custom and diversity: it
had to be interpreted—and consequently was often used—as an expression of
factionalism and of dissent. Eventually, towards the end of the fourth century,
Easter calendar diversity became interpreted as an expression of‘heresy’.
Thefirst manifestation of post-Nicene, calendar factionalism occurred at the
Council of Serdica in 343CE, when a group (probably the majority) of eastern
bishops broke off from the rest of the Council (western bishops, but with some
easterners such as Athanasius), reassembled in a nearby location, and besides
debating on the nature of Christ, constructed for themselves an Easter cycle of
30 years. The document that was drawn up consisted of a list of Jewish Passover
dates from 328 to 343CE, alongside a list of the Christianluna XIVdates from
328 to 357CE, thus 30 years.^140 The dates in both lists were very similar,
but whereas the Jewish Passover always occurred in March, the Christian
luna XIVcould not occur before 21 March: hence if the Jewish Passover was
before 21 March, the Christianluna XIVwas postponed to April.^141
(^138) Why the tide swung in favour of the Alexandrian cycle is studied in detail by Lejbowicz
(2008) = (2010).
(^139) Jones (1943) 55–77. Key evidence is a letter of Paschasinus (written in 443/4CE), on which
see Mosshammer (2008) 62–3.
(^140) The document of the eastern faction of the Serdica Council wasfirst published by
E, Schwartz (1905) 122–3, with facsimile of the 8th-c. manuscript) with significant textual
emendations; for text and discussion see Stern (2001) 74–5, 124–32. See also above, Ch. 6,
near n. 122.
(^141) I am assuming here, for simplicity, the emendations of Schwartz—especially that which
establishes the date ofluna XIVfor 338CEas 21 March (and not April)—even if his emendations
may be open to criticism (see Stern 2001: 126–9).
Sectarianism andHeresy 409