Council of Nicea

The Council of Nicea (or Nicaea; Greek Nikaia) was Christianity's first ecumenical council. It was called by Emperor Constantine in 325 CE to secure for the first time theological cohesion among the churches, especially regarding Christology and ritual practice. There were approximately 250 ranking attendees to debate and decide the future direction of Christianity.

A creed of faith was determined, imposing a single theology on all Christians. The main debate in the council centered on the Christological Arian controversy. The Arians believed that because Christ was the “only begotten” Son of the Father (see the Gospel of John 1:14, 16; 3:16, 18), he was not coeternal with the Father and must necessarily be inferior to Him. They were staunch monotheists and strictly opposed attributing any multiplicity to God. Those holding what is now anachronistically called the “orthodox” view argued that Christ must in all ways be equal to the Father because only God could offer salvation to man. Christ therefore could not be a creature of God but must be God himself incarnate, which would entail Christ's coeternality with the Father. With Constantine's support of the orthodox contingent, the Creed of Nicea was written using the Greek word homoousion, a word found in the philosopher Origen's work, meaning “of the same substance.” It states that Christ is “true God from true God” and affirms God's unity in the face of multiplicity. The Creed also asserted the belief in the Holy Spirit and set the Trinity forever in orthodoxy. All clerics in attendance were required to sign the Creed and all but four did so; two were excommunicated, and two would eventually retract. This signed document of faith made Christianity uniform, at least officially, and became the foundation for all orthodoxy to follow.

Twenty canons were also issued by the Council. These deal with issues of church governance, new and return membership, promotion within church hierarchy, and proper behavior of church governors, as well as determining the preferential status of the Metropolitan sees (Rome, Alexandria, and Antioch, with special mention of Jerusalem). Two canons also provided direction concerning cases of apostasy, mainly involving Novatianists (or Cathars) and Paulinists.

Also at issue at Nicea was the date of Easter. While 14 Nisan in the Jewish calendar had been traditional for the East, Constantine convinced the council not only that all Christians should celebrate the most important day in their calendar at the same time, but that the Jewish calculations should be forsaken in preference of the Roman calendar and calculation. From the close of the council, Easter would be determined by all in the manner of the Roman and Egyptian churches.