Council of Nicaea

The Council of Nicaea was the first ecumenical council, held in 325 CE at the behest of the Roman Emperor Constantine to negotiate a compromise between the orthodox Trinitarians and the Arian heretics. It did not end in compromise and instead ended with the rightful denunciation of the Arians as heretics and the writing of the Nicene Creed, which defined the relationship of the Trinity as one God, who is three persons, the Father, the Son and the Holy Spirit.

The Trinitarians were represented by many major theologians such as Alexander and Athanasius of Alexandria. The heretics were represented by the heresiarch, Arius. Only three out of over three hundred of the attending bishops were opposed to the text of the Nicene Creed.

The next council was the Council of Constantinople.