Division begins in the Church from this Controversy; and Alexander Bishop of Alexandria excommunicates Arius and his Adherents
Having drawn this inference from his novel train of reasoning, he excited many to a consideration of the question; and thus from a little spark a large fire was kindled: for the evil which began in the Church at Alexandria, ran throughout all Egypt, Libya, and the upper Thebes, and at length diffused itself over the rest of the provinces and cities. Many others also adopted the opinion of Arius; but Eusebius in particular was a zealous defender of it: not he of Cæsarea, but the one who had before been bishop of the church at Berytus, and was then somehow in possession of the bishopric of Nicomedia in Bithynia. When Alexander became conscious of these things, both from his own observation and from report, being exasperated to the highest degree, he convened a council of many prelates; and excommunicated Arius and the abettors of his heresy; at the same time he wrote as follows to the bishops constituted in the several cities:—
The Epistle of Alexander Bishop of Alexandria.
To our beloved and most honored fellow-Ministers of the Catholic Church everywhere, Alexander sends greeting in the Lord.
Inasmuch as the Catholic Church is one body, and we are commanded in the holy Scriptures to maintain 'the bond of unity and peace,' it becomes us to write, and mutually acquaint one another with the condition of things among each of us, in order that 'if one member suffers or rejoices, we may either sympathize with each other, or rejoice together.' Know therefore that there have recently arisen in our diocese lawless and anti-christian men, teaching apostasy such as one may justly consider and denominate the forerunner of Antichrist. I wished indeed to consign this disorder to silence, that if possible the evil might be confined to the apostates alone, and not go forth into other districts and contaminate the ears of some of the simple. But since Eusebius, now in Nicomedia, thinks that the affairs of the Church are under his control because, forsooth, he deserted his charge at Berytus and assumed authority over the Church at Nicomedia with impunity, and has put himself at the head of these apostates, daring even to send commendatory letters in all directions concerning them, if by any means he might inveigle some of the ignorant into this most impious and anti-christian heresy, I felt imperatively called on to be silent no longer, knowing what is written in the law, but to inform you of all of these things, that you might understand both who the apostates are, and also the contemptible character of their heresy, and pay no attention to anything that Eusebius should write to you. For now wishing to renew his former malevolence, which seemed to have been buried in oblivion by time, he affects to write in their behalf; while the fact itself plainly shows that he does this for the promotion of his own purposes. These then are those who have become apostates: Arius, Achillas, Aithales, and Carpones, another Arius, Sarmates, Euzoïus, Lucius, Julian, Menas, Helladis, and Gaius; with these also must be reckoned Secundus and Theonas, who once were called bishops. The dogmas they have invented and assert, contrary to the Scriptures, are these: That God was not always the Father, but that there was a period when he was not the Father; that the Word of God was not from eternity, but was made out of nothing; for that the ever-existing God ('the I AM'— the eternal One) made him who did not previously exist, out of nothing; wherefore there was a time when he did not exist, inasmuch as the Son is a creature and a work. That he is neither like the Father as it regards his essence, nor is by nature either the Father's true Word, or true Wisdom, but indeed one of his works and creatures, being erroneously called Word and Wisdom, since he was himself made of God's own Word and the Wisdom which is in God, whereby God both made all things and him also. Wherefore he is as to his nature mutable and susceptible of change, as all other rational creatures are: hence the Word is alien to and other than the essence of God; and the Father is inexplicable by the Son, and invisible to him, for neither does the Word perfectly and accurately know the Father, neither can he distinctly see him. The Son knows not the nature of his own essence: for he was made on our account, in order that God might create us by him, as by an instrument; nor would he ever have existed, unless God had wished to create us.
Source: Ecclesiastical History (New Advent)