Key Facts:

Date 20 May-25 July 325
Location Nicaea
Number of Participants 250-300
Summoned by Constantine
Chaired by Ossius of Cordova
Key Participants Ossius of Cordova, Eusebius of Caesarea, Eusebius of Nicomedia, Alexander of Alexandria, Arius
Key Issues Arianism, Melitians, and the date of Easter
Key Events Most of the bishops subscribed to the Nicene Creed, while those who refused were exiled. The Council also resolved the issue of when to celebrate Easter and drew up twenty canons on various aspects of church order.
Ancient Descriptions Anonymous, HE 2.5-11, 25-35; Athanasius, de Decretis, de Synodis, ad Afros; Eusebius VC 3.4-24; Gelasius, HE, F11-F13; Jerome Dial. con. Luciferanus 20(18), 183; Philostorgius, HE 1.7-10; Rufinus, HE 10.3ff; Socrates, HE 1.8-13; Sozomen, HE 1.17-24; Theodoret, HE 1.7.1-9, 18;       

Ancient Descriptions of the Council of Nicaea

We have arranged the accounts of the Council of Nicaea by several ancient historians into seven tables, displaying the parallel accounts side-by-side.  These tables are available in English and in the original Greek and Latin. They can be accessed here. The documents produced at Nicaea are included in these tables but can also be accessed below.

Surviving Documents:

Constantine’s Summons to the Council


Eusebius’ Letter to his Congregation

Canons (Greek and Latin/English)

The Council’s Letter to the Church in Egypt

Constantine’s Letter to the Church of Alexandria

Constantine’s Letter concerning the Date of Easter


Hanson, R.P.C. The Search for the Christian Doctrine of God (New York: T&T Clark, 1988) pp. 152-163.

Kannengiesser, C. “Nicaea” in The Encyclopedia of the Early Church (New York: Oxford University Press, 1992).

Created by JCB and PSAM

Last updated: 3-21-2023

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