First Council of Nicaea

Condemned Arius' teaching that the Son is a creature who had a beginning (“there was when he was not”) and issued the Nicene Creed, which confesses the Son “of one substance” (homoousios) with the Father. It set principles for a common date of Easter, dealt with the Meletian schism in Egypt and issued 20 canons (e.g. canon 6 on the prerogatives of Alexandria, Rome and Antioch). Some 250–300 bishops attended; tradition gives 318.

Convoked by

Emperor Constantine I

Canons

20

Catholic Church, Eastern Orthodox Church, Oriental Orthodox Churches and the Church of the East; many Protestant churches accept its creed as faithful to Scripture.