(from Theodoret, Ecclesiastical History, I, IV. LPNF, ser. 2, vol. 3, 41.
To his very dear lord, the man of God, the faithful and orthodox Eusebius, Arius, unjustly persecuted by Alexander the Pope, on account of that all conquering truth of which you also are a champion, sendeth greeting in the Lord.
Ammonius, my father, being about to depart for Nicomedia, I considered myself bound to salute you by him, and withal to inform that natural affection which you bear towards the brethern for the sake of God and His Christ, that the bishop greatly wastes and persecutes us, and leaves no stone unturned against us. He has driven us out of the city as atheists, because we do not concur in what he publicly preaches, namely, God always, the Son always; as the Father so the Son; the Son co-exists unbegotten with the God; He is everlasting; neither by thought nor by any interval does God precede the Son; always God, always Son; he is begotten of the unbegotten; the Son is of God Himself. Eusebius, your brother bishop of Caesarea, Theodotus, Paulinus, Athanasius, Gregorius, Aetius, and all the bishops of the East, have been condemned because they say that God had an existence prior to that of his Son; except Philogonius, Hellanicus, and Macarius, who are unlearned men, and who have embraced heretical opinions. Some of them say that the Son is an eructation, others that He is a production, others the He is also unbegotten. These are impieties to which we cannot listen, even though heretics threaten us with a thousand deaths. But we say and believe, and have taught, and do teach, that the Son is not unbegotten; and that He does not derive his subsistence from any matter; but that by His own will and counsel He has subsisted before time, and before ages, as perfect God, only begotten and unchangeable, and that before He was begotten, or created, or purposed, ot established, He was not. For He was not unbegotten. We are persecuted, because we say that the Son has a beginning, but that God is without beginning. This is the cause of our persecution, and likewise, because we say that He is of the non-existent. And this we say, because He is neither part of God, nor of any essential being. For this are we persecuted; the rest you know. I bid thee farewell in the Lord, remembering our afflictions, my fellow-Lucianist, and true Eusebius.