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325
Anno Domini

Ecumenical Council

Council of Nicaea I

May–August 325 Nicaea, Bithynia (modern Turkey) Convoked by: Emperor Constantine I c. 318 bishops 20 canons
Ecumenical Council — Universally Recognised
20Canons
Section I

The Crisis that summoned Council of Nicaea I

The apologetic argument: Defined the Son as consubstantial (homoousios) with the Father against Arius. Rome's endorsement was what made the definition binding — Athanasius later proved this when he appealed to Rome after being condemned by Arian councils.
The Ecumenical Councils

The Seven Ecumenical Councils

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