Event · 325

Council of Nicaea

The first ecumenical council, called by Emperor Constantine at Nicaea in Asia Minor in 325 to settle the dispute over Arius.

History

Causes

Around 318 a quarrel broke out in Alexandria between Bishop Alexander and one of his presbyters, Arius. Arius taught that the Son of God, though higher than every other creature, had a beginning: “before He was begotten, or created, or purposed, or established, He was not.” He set this out in a letter to his ally Eusebius of Nicomedia, complaining that Alexander preached “God always, the Son always” (Theodoret, Ecclesiastical History 1.4). Alexander held that the Son is eternal and that there was never a time when he did not exist. He deposed Arius and wrote to other bishops to explain why (same source, 1.3).

The argument did not stay in Egypt. Arius had friends trained, like him, in the school of Lucian of Antioch, and Eusebius of Nicomedia was close to the court. Eusebius of Caesarea, the church historian, was also sympathetic. By the time Constantine defeated Licinius in 324 and took control of the East, the eastern churches were split. The emperor first tried a letter, telling Alexander and Arius that they were fighting over “small and very insignificant questions” (Eusebius, Life of Constantine 2.64–72). His envoy, Ossius of Córdoba, came back without a settlement. A council at Antioch early in 325 condemned Arius’s position and provisionally excommunicated Eusebius of Caesarea. Constantine then summoned a general council, first to Ancyra and then to Nicaea, near his residence at Nicomedia.

Proceedings

The council met in early summer 325, with the emperor present. Eusebius of Caesarea counted “more than two hundred and fifty” bishops (Life of Constantine 3.6–9); later tradition fixed the number at 318. Almost all came from the Greek-speaking East. The bishop of Rome sent two presbyters, and Ossius represented the West in person. Several delegates still bore scars from the persecution that had ended only a few years earlier.

No minutes survive. What happened has to be pieced together from Eusebius’s letter to his own church, written to explain why he had signed (Letter on the Council of Nicaea), from Athanasius, who attended as Alexander’s deacon and later wrote a defence of the council’s language (De Decretis), and from the fifth-century church historians (Socrates, Church History 1.8–9; Theodoret 1.6–12).

Athanasius’s account is the most useful on how the creed’s wording was reached. The bishops first tried scriptural phrases: the Son is “from God,” the true “image” of the Father, “in” the Father. Each time, he says, the Arian party signalled to one another that they could accept the phrase in their own sense, since all things are “from God” in some way. The majority therefore chose terms that could not be read two ways: the Son is “from the substance (ousia) of the Father” and “of one substance” (homoousios) with him (De Decretis 19–20). Eusebius, for his part, reports that he offered his church’s baptismal creed, that Constantine approved it, and that the council then added homoousios at the emperor’s suggestion. He signed after being told the word implied no division or change in God (Letter, 4–7).

The creed that resulted (text with the canons) ends with anathemas against anyone who says “there was when he was not,” that the Son came “from nothing,” or that he is “of another hypostasis or substance” than the Father. All but two bishops signed. Arius and the two Libyan bishops who refused, Secundus and Theonas, were exiled to Illyricum.

The council also handled practical business. It decided that all churches should keep Easter on the same Sunday, independent of the Jewish calendar, ending the practice of some eastern churches that followed the Jewish reckoning of Passover. The decision survives in the council’s synodal letter to Egypt and in Constantine’s letter to the churches (Life of Constantine 3.17–20), not in the canons. It tried to end the Meletian schism in Egypt. And it issued twenty canons: on the consecration of bishops by at least three others (canon 4), on the regional authority of Alexandria, Rome and Antioch (canon 6), on special honour for Jerusalem (canon 7), on receiving Novatianists back (canon 8), and on standing rather than kneeling for prayer on Sundays and during Pentecost (canon 20) (canons).

Aftermath and influence

The settlement did not hold. Within a few years Eusebius of Nicomedia, who had signed and then been exiled himself, was back in favour. Arius was readmitted by the emperor and died in Constantinople in 336 before he could be restored to communion. Athanasius, bishop of Alexandria from 328, was deposed and exiled five times by emperors and synods. Constantine was baptised on his deathbed in 337 by Eusebius of Nicomedia.

Under Constantius II the pressure ran against Nicaea. A series of councils produced creeds that avoided ousia language, and the twin councils of Ariminum and Seleucia in 359 adopted a formula that the Son is simply “like” the Father. Jerome’s line about that moment became famous: “The whole world groaned, and was astonished to find itself Arian” (Dialogue Against the Luciferians 19).

The way back came through a middle party. Bishops who preferred homoiousios (“of like substance”) turned out to mean much the same thing as Nicaea, and Athanasius said so: those who hesitate only over the word are brothers, not Arians (De Synodis 41). The Cappadocian Fathers, Basil of Caesarea, Gregory of Nazianzus and Gregory of Nyssa, then distinguished one ousia in God from three hypostases, which let the Nicene word stand without implying that Father and Son are one person. The Council of Constantinople in 381 reaffirmed Nicaea, extended its logic to the Holy Spirit, and produced the expanded creed now recited as the Nicene Creed.

Nicaea set two patterns that outlasted the Arian dispute. It made a creed with technical terms the test of orthodoxy, and it made an assembly of bishops from the whole church the body that settles doctrine. Every later council, from Ephesus and Chalcedon onward, presented itself as interpreting Nicaea. Its creed is still shared by Eastern Orthodox, Roman Catholic, Oriental Orthodox, Anglican, Lutheran and most Reformed churches, and remains the main doctrinal statement that divided Christians hold in common.

Key ideas and contributors

The Son is fully God. The council’s central claim is that whatever the Father is as God, the Son is too. “God from God, Light from Light, true God from true God, begotten not made” rules out any reading in which the Son is a very high creature. For the Nicene party this was a question of salvation: only God can unite humanity to God, and Christians had always worshipped Christ (John 1:1; John 10:30). See God and Trinity and Christ.

Begotten is not made. Arius treated “begotten” and “created” as near-synonyms and leaned on Proverbs 8:22, where Wisdom says the Lord “created me at the beginning of his work” (as the Greek Old Testament reads). Alexander and Athanasius insisted that the Son’s begetting is eternal and unlike any creature’s coming into being. Athanasius’s Orations Against the Arians (c. 340) quote Arius’s poem Thalia and answer it line by line.

Homoousios. The council’s key word meant that the Son shares the Father’s very being, not a similar or derived one. Athanasius later argued that the bishops chose it reluctantly, because scriptural phrases alone had proved too easy to evade, and that a non-scriptural word was justified if it guarded the scriptural sense (De Decretis 19–21).

A council speaks for the whole church. Constantine called the council, but its authority came to rest on the claim that the bishops together, gathered from across the empire, expressed the faith handed down from the apostles. Athanasius pressed the point against those who wanted to revise Nicaea: an ecumenical council’s decision could not be reversed by later local synods (De Decretis 2–4). This idea underlies Conciliarity and Holy Tradition.

Other contributors: Alexander of Alexandria, who first condemned Arius; Ossius of Córdoba, who probably presided; Eustathius of Antioch and Marcellus of Ancyra, the council’s sharpest anti-Arian voices; and Eusebius of Caesarea, whose reluctant signature and explanatory letter are the best window into the debate from the middle ground.

Key controversies

A word not in Scripture. The objection raised immediately, and repeated for decades, was that homoousios is not a biblical term. Worse, a council at Antioch around 268 was remembered as having rejected the word in condemning Paul of Samosata, which Athanasius had to explain away (De Synodis 43–45). Many eastern bishops also feared the word was Sabellian, making Father and Son a single person under two names. That fear was not baseless: Marcellus of Ancyra, a leading Nicene, held views close to that, and the creed’s anathema against “another hypostasis or substance” seemed to treat hypostasis and ousia as the same thing. The confusion was only cleared up after 362 by the Cappadocian distinction.

The emperor’s role. Constantine summoned the council, attended it, according to Eusebius proposed its key word, and enforced the outcome with exile. Some later writers saw this as the moment the church accepted state power over doctrine; others note that the same emperor and his son later backed the other side, and that Nicaea eventually won despite imperial pressure, not because of it. The debate over “Constantinian” Christianity runs through Anabaptist and later free-church criticism of established churches.

What “Arianism” was. Modern historians question the old picture of a single heresy against a single orthodoxy. R. P. C. Hanson’s The Search for the Christian Doctrine of God (1988), Rowan Williams’s Arius: Heresy and Tradition (1987) and Lewis Ayres’s Nicaea and Its Legacy (2004) argue that “Arian” was largely Athanasius’s polemical label for a wide range of eastern theologians, many of whom owed nothing to Arius, and that Nicene orthodoxy itself took shape only over the following sixty years. A short secondary overview is the Wikipedia article (secondary). See Arianism for the losing side’s case.

Popular myths. Nicaea is often said to have voted Jesus divine by a narrow margin or to have chosen the books of the Bible, claims spread widely by Dan Brown’s novel The Da Vinci Code (2003). Neither has support in the sources. The vote was overwhelming, the debate was over what kind of divinity the Son has, not whether he has any, and no source says the council discussed the biblical canon. The story of Nicholas of Myra striking Arius at the council comes from much later hagiography: the earliest known text, Petrus de Natalibus’s late fourteenth-century catalogue of saints, has Nicholas strike only “a certain Arian,” and Arius himself is named first in a sixteenth-century Life (Roger Pearse, secondary).

Easter. Nicaea’s goal of one Easter for all churches failed in the long run. The council laid down no formula in its canons, and Alexandria and Rome computed the date differently for centuries. Since the West adopted the Gregorian calendar in 1582, eastern and western churches usually celebrate on different Sundays. The 1700th anniversary of the council in 2025, a year when both dates happened to fall on the same day, renewed calls from Catholic and Orthodox leaders for a common date (EWTN News, secondary).

What remains unresolved

Nicaea’s creed is the most widely shared doctrinal text in Christianity, so the live questions are less about its content than its authority. Eastern Orthodox and Roman Catholic churches treat it as binding because an ecumenical council issued it. Most Protestants accept it because they judge it faithful to Scripture, which leaves open what they would do if a council erred (see Sola Scriptura). And the later Western addition of the Filioque to the creed’s 381 form is still the clearest example of how a shared text can divide the churches that recite it.