The movement for denying the full Godhead of Christ and making Him a creature took its title from one Areios (in the Latin form Arius), a Greek-speaking African cleric rather older than Constantine, and already famous as a religious force some years before Constantine’s victories and first imperial power.
Remember that Arius was only a climax to a long movement. What was the cause of his success? Two things combined. First, the momentum of all that came before him. Second, the sudden release of the Church by Constantine. To this should be added undoubtedly something in Arius’ own personality. Men of this kind who become leaders do so because they have some personal momentum from their own past impelling them. They would not so become unless there were something in themselves.
I think we may take it that Arius had the effect he had through a convergence of forces. There was a great deal of ambition in him, such as you will find in all heresiarchs. There was a strong element of rationalism. There was also in him enthusiasm for what he believed to be the truth.
His theory was certainly not his own original discovery, but he made it his own; he identified it with his name. Further, he was moved to a dogged resistance against people whom he thought to be persecuting him.
He suffered from much vanity, as do nearly all reformers. On the top of all this a rather thin simplicity, “commonsense,” which at once appeals to multitudes. But he would never have had his success but for something eloquent about him and a driving power.
He was already a man of position, probably from the Cyrenaica (now an Italian colony in North Africa, east of Tripoli), though he was talked of as being Alexandrian, because it was in Alexandria that he lived. He had been a disciple of the greatest critic of his time, the martyr Lucian of Antioch. In the year 318 he was presiding over the Church of Bucalis in Alexandria, and enjoyed the high favour of the Bishop of the City, Alexander.
Arius went over from Egypt to Caesarea in Palestine, spreading his already well-known set of rationalizing, Unitarian ideas with zeal. Some of the eastern Bishops began to agree with him. It is true that the two main Syrian Bishoprics, Antioch and Jerusalem, stood out; but apparently most of the Syrian hierarchy inclined to listen to Arius.
When Constantine became the master of the whole Empire in 325, Arius appealed to the new master of the world. The great Bishop of Alexandria, Alexander, had excommunicated him, but reluctantly. The old heathen Emperor Licinius had protected the new movement.
A battle of vast importance was joined. Men did not know of what importance it was, violently though their emotions were excited. Had this movement for rejecting the full divinity of Our Lord gained the victory, all our civilization would have been other than what it has been from that day to this. We all know what happens when an attempt to simplify and rationalize the mysteries of the Faith succeeds in any society. We have before us now the ending experiment of the Reformation, and the aged but still very vigorous Mohammedan heresy, which may perhaps appear with renewed vigour in the future. Such rationalistic efforts against the creed produce a gradual social degradation following on the loss of that direct link between human nature and God which is provided by the Incarnation.
Human dignity is lessened. The authority of Our Lord is weakened. He appears more and more as a manperhaps a myth. The substance of Christian life is diluted. It wanes. What began as Unitarianism ends as Paganism.
To settle the quarrel by which all Christian society was divided, a council was ordered by the Emperor to meet, in A.D. 325, at the town of Nicaea, fifty miles from the capital, on the Asiatic side of the Straits.
The Bishops were summoned to convene there from the whole Empire, even from districts outside the Empire where Christian missionaries had planted the Faith. The great bulk of those who came were from the Eastern Empire, but the West was represented, and, what was of the first importance, delegates arrived from the Primatial See of Rome; but for their adherence the decrees of the Council would not have held. As it was their presence gave full validity to these Decrees. The reaction against the innovation of Arius was so strong that at this Council of Nicaea he was overwhelmed. —from The Great Heresies (1938)