Few Christians are aware that two of the most fundamental doctrines of the Christian faith – the divinity of Jesus Christ and the Trinity – were not finally decided until 300 years after the death of Jesus. Both doctrines were forged in the fourth century out of the religious and political firestorm sparked by Arius, a popular presbyter of the church in Alexandria, Egypt.

Arius had a simple formula for explaining how Jesus Christ could be divine – and therefore worthy of worship along with God the Father – even though there is only one God. The simple formula taught by Arius was well received by the common believers in Alexandria, but not by Arius’ supervisor, bishop Alexander. Each man lined up supporters, and the battle lines were drawn for what history would call the Arian Controversy. This bitter ordeal for the Christian churches of the Roman Empire began in A.D. 318, led to the Creed of Nicea in 325 and finally ended with the Nicene Creed expanded and established at the Council of Constantinople in 381.


Church Fathers from as early as the late 100s had been writing that the Word of God, the Logos of John 1:1-2, was co-eternal with the Father – and therefore uncreated and without beginning. The presbyter Arius was not the first to dispute this. Similar challenges had already arisen by the late second and early third centuries in the form of Monarchianism.

Monarchians fell into two broad categories. The Adoptionist or Dynamic Monarchians held that Jesus was only a man in whom dwelled the power of the supreme God.1 The Modalist Monarchians taught that God revealed himself in three modes – as Father, Son and Spirit – but never at the same time. This preserved the idea of the full divinity of the Son, but at the expense of any real distinction between the Son and the Father. Some Modalists believed that Jesus Christ was actually the Father in the flesh. All forms of Monarchianism were eventually branded as erroneous and rejected as heresy by the Christian churches across the empire.


In one sense, Arius was simply the latest thinker to try to reconcile monotheism (belief in one God) with the Christian belief that Jesus Christ was divine. But there was a great difference between Arius’ attempt and all previous efforts. No longer was Christianity an unsanctioned, often underground and persecuted religion. Now the Roman emperor Constantine had given Christianity unprecedented legitimate status in the Empire, so that the question of who Jesus is could finally come before the whole church to be settled.

Arius was a popular senior presbyter in charge of Baucalis, one of the twelve “parishes” of Alexandria in the early fourth century.2 By A.D. 318, Arius had begun teaching his followers that the Son of God (who is also the Logos or Word of John 1:1-2) did not exist until the Father brought him into existence. To Arius, the Father first created the Word, and then the Word, as the Father’s unique and supreme agent, created everything else.

Arius’ idea seemed to preserve monotheism as well as uphold the divinity of the Son, even if it was a bestowed divinity given to him, as distinct from the inherent and eternal divinity of the Father. With the help of catchy rhymes and tunes, Arius’ ideas quickly caught on among the common converts of Alexandria.


Alexander, the bishop of Alexandria, and his assistant, a presbyter named Athanasius, saw great danger in Arius’ teaching and took action to arrest it. Contrary to Arius’ teaching that God was once without the Word, Alexander asserted that God cannot be without the Word, and that the Word is therefore without beginning and eternally generated by the Father.

Alexander sent letters to neighboring bishops requesting support and convened a council at Alexandria that excommunicated Arius and a dozen other clergy.3 Arius also sought backing, however, and obtained the support of several leaders, including Eusebius, the bishop of Nicomedia. Eusebius enjoyed a close relationship with Emperor Constantine, which would play a major role in the unfolding of the controversy. Another supporter of Arius was Eusebius of Caesarea, whose history of the early Christian church is still available today.

Constantine steps in

The Emperor Constantine became aware of the developing problem, and saw a need to resolve it. As Emperor, Constantine’s concern was not so much for the unity of the church as for the unity of the empire. Theologically, he viewed it as a “trifle.”4 Constantine’s first move was to send his religious advisor, Bishop Hosius of Cordova, Spain, to sort out the differences. Hosius was unsuccessful in bringing Arius and Alexander to peace, but he presided over a council in Antioch in early 325 that condemned Arianism and censured Eusebius of Caesarea.5 But the division continued, so Constantine called a council of the church to settle the dispute.

Constantine asked that the council be held at Nicaea, a city close to his headquarters in Nicomedia. The emperor opened the council in June 325 with about 300 bishops present (most from the east). Constantine was looking for mutual tolerance and compromise. Many of the bishops present were also apparently prepared to find compromise.

As the proceedings unfolded, however, thoughts of compromise quickly eroded. Once the tenets of the Arian position became clear, it did not take long for them to be rejected and condemned. The ideas that the Son of God is God only as a “courtesy title” and that the Son is of created status were vehemently denounced. Those who held such views were declared to be heretics. The divinity of the Logos was upheld, and the Son was declared to be “true God” and co-eternal with the Father. The key phrase from the Creed established at Nicaea in 325 was “of the essence of the Father, God of God and Light of Light, very God of very God, begotten, not made, being of one substance with the Father.”

Homoousios (of the same essence) was the key Greek word. It was intended to convey, against the Arians, that the Son is equally divine with the Father. This it did, but it did not answer the question of how the Son and the Father, if they are of the same essence, are also distinct. Conse­quently, though Arianism was condemned and Arius banished, the Council of Nicaea did not see an end to the controversy.

A little letter makes a big difference

Athanasius and most other eastern bishops said that the Son was homoousias with the Father, meaning “of the same essence.” The Arian theologians disagreed, but suggested a compromise: they could accept the word with the addition of only one letter, the smallest Greek letter, the iota. They said that the Son was homoiousias with the Father – a Greek word meaning “similar essence.”

But similarity is in the “i” of the beholder, and the Arians actually meant that Jesus was not the same kind of being as the Father. It would be like saying that he was “almost” divine. The orthodox theologians could not accept that, and would not accept a word that allowed such an unorthodox interpretation.

Imperial reversals

Eusebius of Nicomedia, who presented the Arian cause to the Council and was deposed and banished for it, enjoyed a close personal relationship with Emperor Constantine. In time, he was able to convince Constantine to ease the punishment on the Arians, and to recall Arius from exile. Eventually, after a council at Jerusalem formally acquitted him of the charge of heresy in 335, Arius was to have been received back into the fellowship of the church in Constantinople. Philip Schaff wrote:

But on the evening before the intended procession from the imperial palace to the church of the Apostles, he suddenly died (A.D. 336), at the age of over eighty years, of an attack like cholera, while attending to a call of nature. This death was regarded by many as a divine judgment; by others, it was attributed to poisoning by enemies; by others, to the excessive joy of Arius in his triumph.6

Athanasius, meanwhile, had succeeded Alexander as bishop of Alexandria in 328 only to be condemned and deposed by two Arian councils, one at Tyre under the presidency of Eusebius of Caesarea, and the other at Constantinople in about 335. He was then banished by Constantine to Treves in Gaul in 336 as a disturber of the peace of the church.7

This turn of events was followed by the death of Constantine in 337 (who received the sacrament of baptism on his deathbed from the Arian bishop Eusebius of Nicomedia). Constantine’s three sons, Constantine II, Constans, and Constantius succeeded him. Constantine II, who ruled Gaul, Great Britain, Spain, and Morocco, recalled Athanasius from banishment in 338. In the east, however, matters were different. Constantius, who ruled the east, was Arian. Eusebius of Nicomedia, the leader of the Arian party, was appointed Bishop of Constantinople in 338. Before long, war in the west between Constantine II and Constans gave Constantius a free hand to again exile Athanasius in 340.

When Constantine II died, however, and the western empire was united under Constans, Constantius had to follow a more moderate line with the Nicene party. The two emperors called a general council in Sardica in 343, presided over by Hosius, at which the Nicene doctrine was confirmed. Constans also compelled Constantius to restore Athanasius to his office in 346.8


When Constans died in 350, the pendulum swung again. Constantius, now the sole emperor and still Arian, held councils supporting Arianism and banished bishops who opposed their edicts, including Hosius and Athanasius. By now, however, Arianism had become divided into two factions. One party had slightly modified its position to affirm homoiousios, or similarity of essence, rather than the original heteroousios, or difference of essence, still held by the strictest Arians.

This “compromise,” sometimes called “semi-Arianism,” still represented an unbridgeable chasm from the orthodox homoousios, or same essence. It only served to pit the Arians against one another. For Nicenes who still had difficulty with the apparent lack of distinction between the Father and the Son represented by homoousios, though, the semi-Arian homoiousios did, for a time, afford a reasonable compromise. In any case, by the time Constantius died, the church had become Arian, at least on the surface.

Imperial reversals

It was the death of Constantius in 361 that set the stage for the permanent triumph of Nicene faith. Julian the Apostate (who was not a Christian) became emperor and implemented a policy of toleration for all the Christian parties. Though Julian’s policy seems positive toward Christianity, his real hope was that the opposing factions would destroy one another. He recalled the exiled bishops, including Athanasius (though Athanasius was soon banished again as an “enemy of the gods” but was again recalled by Julian’s successor Jovian).9

It was through the efforts of Athanasius that the concerns of the Nicenes and the semi-Arians about blurring the distinction between the Father and the Son were satisfied. Athanasius argued that homoousios could be interpreted in such a way as to affirm the same essence as long as the distinction between the Father and Son were not destroyed. He made it plain that “same essence” must retain the unity but never be allowed to destroy the distinctions in the Godhead. With this understanding, along with the compelling work of three Cappadocian bishops, Basil, Gregory of Nazianzus, and Gregory of Nyssa, the Nicene faith again began to gain ascendancy.

Julian died in 363, and was followed by Jovian, who was favorable toward Athanasius and the Nicene faith. His reign was short, though, ending in 364. He was succeeded by Valens, a fanatical Arian, whose intensity against both semi-Arians and Nicenes tended to bring those two parties together. In 375, he was followed by Gratian, who was of Nicene faith, and who recalled all the exiled orthodox bishops.

By the end of Gratian’s reign, Arianism was greatly waning in intellectual defense and in morale. It was the long reign of Theodosius I, who was educated in the Nicene faith, that finally ended the controversy. He required all his subjects to confess the orthodox faith. He appointed a champion of Nicene faith, Gregory of Nazianzus, as patriarch of Constantinople in 380. In 381, Gregory presided over the Council of Constantinople.

The Council of Constantinople

The Council of Constantinople affirmed the Creed of Nicea, altering it only slightly and in non-essential ways. It is the form of the Creed adopted at Constantinople that today bears the name Nicene Creed. The controversy was at last ended in the empire. However, Arianism would continue to impact the church for the next two centuries in the form of the various peoples outside the empire who had become Christians according to the Arian faith (most of whom scarcely even knew the difference).

Athanasius, who had so diligently and unswervingly opposed the Arian heresy, did not live to see the conflict ended. He died in 373 in his native Alexandria. In the end, the unyielding Athanasius is a fair representation of the unyielding truth of the orthodox Christian faith. Fundamental to the validity of Christianity is the reality of redemption, made possible only by the work of a being no less than true God, the Lord Jesus Christ.

Arius believed that a Christ designated as divine by virtue of his special creation could serve as true Redeemer and true Mediator between God and humanity. It took the dogged, relentless, unwavering faith of an Athanasius to hold fast to the truth that no being less than true God could reconcile humanity to God.

The apostle Paul wrote to the church in Corinth: “No doubt there have to be differences among you to show which of you have God’s approval” (1 Corinthians 11:19). Likewise, the Arian controversy became an essential waypoint on the journey of the church, for despite the trial and pain of controversy, the truth of the nature of the divine One who had come to redeem humanity had to be made plain.

Who was who?

  • Arius (c. 250-336): Theologian in Alexandria, Egypt, a presbyter (an elder) of the church. He taught his followers that the Son of God did not exist until he was brought into existence by the Father.
  • Alexander of Alexandria (d. 326): Bishop of Alexandria and Arius’ supervisor. He strongly opposed Arianism.
  • Athanasius (293-373): A presbyter of the church in Alexandria and assistant to Bishop Alexander. He later succeeded Alexander as Bishop of Alexandria and spearheaded the effort to oppose Arianism and establish the Nicene faith.
  • Eusebius of Caesarea (c. 263-339): Bishop of Caesarea and author of several works chronicling the history of early Christianity, including Ecclesiastical History. He hoped for a compromise in the Arian controversy, and as a historian he recorded the proceedings at the Council of Nicea.
  • Eusebius of Nicomedia (d. 341): Bishop of Nicomedia. He supported Arius’ ideas and presented the Arian side of the controversy at the Council of Nicea.
  • Constantine the Great (272-337): Emperor of the Roman Empire who legalized Christianity in the Empire. He called the Council of Nicea in an effort to bring an end to the dispute among the churches that was threatening the security of the Empire.
  • Hosius of Cordova (c. 256-358): Bishop of Cordova, Spain. He was sent to Alexandria by Constantine to mediate the Arian controversy.


1 Clyde Manschreck, “Monarchianism,” in Dictionary of Bible and Religion (Nashville: Abingdon, 1986), 704.

2 David Wright, “Councils and Creeds,” The History of Christianity (Herts, England: Lion Publishing, 1977), 156.

3 Wright, 157.

4 Wright, 159.

5 William Rusch, The Trinitarian Controversy (Philadelphia: Fortress, 1980), 19.

6 Philip Schaff, History of the Christian Church (Charles Scribner’s Sons, 1910; reprinted by Eerdmans, 1987), vol. III, 663.

7 Schaff, 663.

8 Schaff, 635.

9 Schaff, 638.

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Last modified: Friday, January 18, 2019, 2:21 PM