Thinking allowed

Nicaea and the date of Easter

This art­icle was first pub­lished in the June 2025 issue of Trans­form­ing Wor­ship News (formerly Prax­is News of Wor­ship).

The date of East­er is often regarded as rather com­plic­ated, too com­plic­ated for nearly every­one to worry about. But it links us with the ori­gin of the annu­al fest­iv­al, and the way the early Church cel­eb­rated the resurrection.

When the Emper­or Con­stantine decided that Chris­tian­ity was the best hope of uni­fy­ing his empire, he found dis­agree­ment on sev­er­al top­ics, includ­ing the nature of Christ and the date on which to hold an annu­al cel­eb­ra­tion of his resur­rec­tion. The Coun­cil of Nicaea in 325 attemp­ted to resolve both issues, agree­ing a state­ment of belief and form­al­iz­ing the date of Easter.

The story begins with the Jew­ish fest­iv­al of Pas­sov­er, held at the first full moon of the spring, when the moon lights the sky all night. In the Jew­ish lun­ar cal­en­dar this day is 15 Nis­an, and the pre­vi­ous day, 14 Nis­an, is the day of pre­par­a­tion. In the late after­noon of that day, until the Temple was des­troyed, Pas­sov­er lambs were slaughtered in the Temple pre­cincts. They were then roas­ted and eaten at the Pas­sov­er meal that began with the full moon at sun­set, the start of 15 Nis­an. In the fourth gos­pel, the cru­ci­fix­ion was on 14 Nis­an, and in the syn­op­tics on 15 Nisan.

There is no expli­cit evid­ence in the New Test­a­ment of a yearly East­er. The focus in the early Church was the weekly cel­eb­ra­tion of the resur­rec­tion on the first day of the week, every Sunday. Although it is not entirely clear – and there may have been a cov­er up – it seems that Chris­ti­ans in Jer­u­s­alem and the Jew­ish dia­spora did keep an annu­al fest­iv­al, but Gen­tile Chris­ti­ans prob­ably didn’t. The former group kept an annu­al cel­eb­ra­tion of both the cru­ci­fix­ion and resur­rec­tion on 14 Nis­an, whichever day of the week that fell on.

Per­haps influ­enced by this annu­al feast kept in the dia­spora, oth­er Chris­ti­ans began to observe it and a fast on the pre­vi­ous day. But rather than keep­ing it on 14 Nis­an they cel­eb­rated the fol­low­ing Sunday, the day of the weekly com­mem­or­a­tion of the resur­rec­tion. Per­haps just as today, it was more con­veni­ent to trans­fer week­day fest­ivals to  Sunday.

These two groups co-exis­ted until at the end of the second cen­tury, Pope Vic­tor I con­tro­ver­sially excom­mu­nic­ated those who kept 14 Nis­an – the Quar­to­de­cimans (or “four­teen­ers”). A cen­tury later the dis­pute had not ended although the Quar­to­de­cimans were a dis­tinct minor­ity. So when, com­manded by Con­stantine to agree a com­mon date, the bish­ops assembled at Nicaea it was not sur­pris­ing that major­ity opin­ion, favoured by Rome and oth­er major sees, pre­vailed. The Coun­cil ruled that the annu­al paschal feast, cel­eb­rat­ing the resur­rec­tion, should be observed on the Sunday after the first full moon of the spring, the full moon after the equinox.

The Coun­cil did not pre­scribe how this might be determ­ined in advance, and ini­tially it was per­haps left to dir­ect obser­va­tion. Com­pet­ing tables of dates soon emerged, fre­quently based on a 19-year lun­ar cycle that had been known since at least the Baby­lo­ni­ans. The date of the equi­nox, which in the first cen­tury had fallen on 25 March, had by the fourth cen­tury drif­ted to 21 March. Tables from Alex­an­dria were gen­er­ally regarded as the best, and the declar­a­tion each year from that see of the date of East­er was usu­ally fol­lowed, though for many years the see of Rome used dif­fer­ent tables so occa­sion­ally East­er would fall on anoth­er date. Even­tu­ally the tables com­piled and exten­ded by the sixth-cen­tury monk Dionysi­us Exiguus were accep­ted as defin­it­ive. These con­tin­ued in use through­out the Church, across the schism between East and West. As the middle ages wore on it was recog­nised that both lun­ar and sol­ar com­pon­ents of the tables were increas­ingly inac­cur­ate, but it was not until after the Reform­a­tion that Pope Gregory XIII uni­lat­er­ally intro­duced a mod­i­fied cal­en­dar with self-cor­rect­ing lun­ar tables. Although these were gradu­ally accep­ted by the churches of the Reform­a­tion they have not been adop­ted in the East, at least not for determ­in­ing Easter.

In the twen­ti­eth cen­tury there were some moves to fix the date of East­er, but at the end of the cen­tury the World Coun­cil of Churches pro­posed abol­ish­ing cal­cu­lated tables based on the approx­im­ate 19-year cycle and instead using accur­ate astro­nom­ic­al cal­cu­la­tions of the equi­nox and the full moon as observed in the time zone of Jer­u­s­alem. They sug­ges­ted this might be adop­ted in 2000 when both East­ern and West­ern cal­cu­la­tions coin­cided on the same date. There was some sup­port for this from Rome, from Anglic­ans and vari­ous churches of the Reform­a­tion and some Ortho­dox churches, but it was far from uni­ver­sal. In this 1700th anniversary year of Nicaea, when East­er dates again coin­cide, the WCC has re-iter­ated its pro­pos­al. Once again, it seems unlikely to gain enough sup­port to be brought in.


Simon Ker­shaw remem­bers try­ing to cal­cu­late East­er from the tables in the BCP while endur­ing long ser­mons as a young chor­is­ter at Even­song. He has con­tin­ued to cal­cu­late and write about the date of Easter.

2 comments

  • Martin Hughes says:

    Isn’t it pos­sible that the first oppon­ents of the Quar­to­de­cimans, who based them­selves on John’s Gos­pel, were really ‘Quin­to­de­cimans’, who based them­selves on the Syn­op­tic chro­no­logy and thought that Jesus had died on the 15th?
    Euse­bi­us led the way for us to regard the argu­ment as date versus day, when its real basis was date versus date. To this day there is hardly any con­scious­ness of this import­ant New Test­a­ment crux

    • Simon Kershaw says:

      Thanks for your com­ments. As I men­tioned else­where, the art­icle is a bit of a canter across the field, lim­ited primar­ily by the word count allowed in a print pub­lic­a­tion. Although I did men­tion the chro­no­lo­gic­al dif­fer­ence between the Syn­op­tics and the Fourth Gos­pel, I did rather gloss over it.

      I should per­haps add a short bib­li­o­graphy – primar­ily Tal­ley’s Ori­gins of the Litur­gic­al Year and Brad­shaw’s Pas­sov­er and East­er: Ori­gin and His­tory to Mod­ern Times and Ori­gins of Feasts, Fasts and Sea­sons in Early Chris­tian­ity. Also Mossham­mer­’s East­er Com­pu­tus and the Ori­gins of the Chris­ti­an Era.

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