Nicaea I — First Ecumenical Council

Timeline Event · 325 CE

Nicaea confesses the Son as true God, of one essence with the Father, against Arian subordination.

Historical context

Alongside its confession about the Son and its disciplinary canons, Nicaea seeks agreement about celebrating Easter. The synodal letter to the Egyptians reports that agreement; Constantine's circular, preserved by Eusebius, presents an imperial account of its significance. These are different documents and voices.

Key points

The twenty surviving numbered canons are not a detailed algorithm for computing Easter.
The synodal letter is direct evidence that a common observance was sought.
Constantine's circular in Life of Constantine III.17-20 is an imperial interpretation, not interchangeable with the council's creed or canons.

People

Constantine
Alexander of Alexandria
Athanasius
Arius

Primary sources

The creed confesses the Son:

The Nicene creed confesses the Son as of one substance with the Father.

being of one substance (ὁμοούσιον, consubstantialem) with the Father
— First Council of Nicaea, Nicene Creed (Creed), trans. Henry Percival, Nicene and Post-Nicene Fathers, Second Series, Volume 14

Passage context and translation

The council uses the term homoousios to confess the Son's full divinity against Arian claims that the Son is a creature.

Before the excerpt

very God of very God, begotten (γεννηθέντα), not made,

After the excerpt

By whom all things were made, both which be in heaven and in earth.

Percival translation in Nicene and Post-Nicene Fathers, Second Series, Volume 14; the excerpt retains the Greek and Latin gloss printed in the linked edition.

Sources and further reading

Nicaea: creed, twenty canons, and synodal letter (Conciliar texts in public-domain translation)
Henry Percival's NPNF translation prints the distinct documents. The letter's announcement is not a twenty-first numbered calculation canon.
Constantine's circular on the council and Easter (Imperial letter within a later celebratory biography)
Read the claim of unity and the hostile rhetoric critically. Eusebius's praise of the emperor and Constantine's words are distinct from conciliar legislation.
OCA: The Seven Ecumenical Councils (Inherited Orthodox doctrinal introduction)
Retained introduction to Orthodox reception; the original Christological overview remains unchanged.

Related records

The Holy Trinity (Catechumen Module)
Church History (Catechumen Module)
The Ecumenical Councils (Catechumen Module)
First Council of Nicaea (Council)
The Trinity (Formation Module)
Councils and Teaching (Formation Module)
The Trinity (Formation Module)
Athanasius of Alexandria (Church Father)
From Nicaea to Constantinople: the Trinitarian debate (Church History)
Dionysius links an Easter table with years from Christ's incarnation (Timeline Event)
Aleppo consultation proposes a common calculation of Easter (Timeline Event)

Open Timeline in the interactive atlas

All records