Council of Nicaea

Background

In the early fourth century, Arius, a presbyter of the church in Alexandria, Egypt, taught that the Son (Jesus Christ) is not eternal as the Father is. He held that the Son was a being created out of nothing before the creation of the world. Bishop Alexander of Alexandria excommunicated Arius. However, when Eusebius of Nicomedia and others came to Arius's support, the controversy spread throughout the Eastern Church. There were also two other sources of conflict. One was the Melitian schism, which arose over conduct during persecution; the other was the differing dates on which various regions observed Easter. Constantine I, who became sole emperor of the Roman Empire in 324, convened an empire-wide council of bishops to resolve the divisions in the church.

Proceedings

• May 325: The council met at the imperial residence in Nicaea in Asia Minor (present-day İznik, Turkey). Sources differ on when the council concluded, placing its close anywhere from June to August.
• Participants: Estimates of the number of bishops range from 250 to 318. The figure of 318 comes from Athanasius and is the one traditionally cited. Most participants were bishops of the Eastern Church. Hosius of Córdoba is believed to have presided over the council.
• Doctrinal decisions: The council adopted a creed confessing that the Son is consubstantial with the Father. "Consubstantial" renders the Greek term homoousios, meaning "of the same substance." The council condemned the teaching of Arius (Arianism). Most bishops signed the creed, and those who refused were exiled along with Arius. Athanasius, who accompanied Alexander, is said to have played a major role in refuting Arius.
• Other decisions: The council determined that all churches should observe Easter on the same Sunday. Melitius was allowed to retain only the title of bishop, without authority to ordain clergy. The council also issued twenty canons concerning church order, addressing matters such as the election of bishops and the readmission to the church of those who had renounced the faith during persecution.

Outcome and Influence

Even after the council, disputes over the term "consubstantial" continued for several decades. The Council of Constantinople in 381 expanded the Nicene Creed, adding, among other things, a confession concerning the Holy Spirit. What is commonly called the Nicene Creed today is this expanded creed. The Council of Nicaea marked the beginning of the series of ancient councils that extended to the Council of Chalcedon (451). Its decisions became the standard for the doctrines of the Trinity and Christology. Not only the Catholic Church and the Eastern Orthodox Church but also many Protestant traditions, including the Lutheran, Anglican, and Reformed churches, accept the council's doctrinal decisions. It is distinct from the Second Council of Nicaea of 787, which addressed the question of icons. In 2025, on the council's 1,700th anniversary, Korean Christian media also revisited its significance.

Assessment

• Most denominations regard the council as the church's public affirmation of the deity of Christ as attested in Scripture. Although the term "Trinity" does not appear in the Bible, Korean Christian circles, like others, commonly explain that the doctrine summarizes the core of biblical teaching.
• Some critics, pointing to the emperor's role in convening the council and his influence over it, view it as an instance of political power intervening in doctrinal decisions.
• The World Mission Society Church of God claims that the Passover was abolished at this council and emphasizes the emperor's political motives. Standard accounts of church history describe this decision as the unification of the date of Easter.