Today we commemorate the Ecumenical Council of Nicaea. Convoked in AD 325 by Roman Emperor Constantine, the Council of Nicaea ruled against the Arians, who taught that Jesus was not the eternal Son of God, but was a created being. The chief opponents of the Arians were Alexander, Bishop of Alexandria, and Athanasius, deacon to Alexander. It was at this council that an early version of the Nicene Creed was adopted — the full version being adopted in its entirety at the Council of Constantinople in AD 381.