About this time, Eunomius, who had held the church in Cyzicus in place of Eleusius, and who presided over the Arian heresy, devised another heresy besides this, which some have called by his name, but which is sometimes denominated the Anomian heresy. Some assert that Eunomius was the first who ventured to maintain that divine baptism ought to be performed by one immersion, and to corrupt, in this manner, the apostolical tradition which has been carefully handed down to the present day. He invented, it is said, a mode of discipline contrary to that of the Church, and disguised the innovation under gravity and greater severity. He was an artist in words and contentions, and delighted in arguments. The generality of those who entertain his sentiments have the same predilections. They do not applaud a good course of life or manner, or mercy towards the needy, unless exhibited by persons of their own sect, so much as skill in disputation and the power of triumphing in debates. Persons possessed of these accomplishments are accounted pious above all others among them. Others assert, I believe more truthfully, that Theophronius, a native of Cappadocia, and Eutychius, both zealous propagators of this heresy, seceded from communion with Eunomius during the succeeding reign, and innovated about the other doctrines of Eunomius and about the divine baptism. They asserted that baptism ought not to be administered in the name of the Trinity, but in the name of the death of Christ. It appears that Eunomius broached no new opinion on the subject, but was from the beginning firmly attached to the sentiments of Arius, and remained so. After his elevation to the bishopric of Cyzicus, he was accused by his own clergy of introducing innovations in doctrine. Eudoxius, ruler of the Arian heresy at Constantinople, summoned him and obliged him to give an account of his doctrines to the people; finding, however, no fault in him, Eudoxius exhorted him to return to Cyzicus. Eunomius, however, replied, that he could not remain with people who regarded him with suspicion; and, it is said, seized the opportunity for secession, although it seems that, in taking this step he was really actuated by the resentment he felt at the refusal which Aëtius, his teacher, had met with, of being received into communion. Eunomius, it is added, dwelt with Aëtius, and never deviated from his original sentiments. Such are the conflicting accounts of various individuals; some narrate the circumstances in one way, and some in another. But whether it was Eunomius, or any other person, who first made these innovations upon the tradition of baptism, it seems to me that such innovators, whoever they may have been, were alone in danger, according to their own representation, of quitting this life without having received the divine baptism; for if, after they had been baptized according to the mode recommended from the beginning, they found it impossible to rebaptize themselves, it must be admitted that they introduced a practice to which they had not themselves submitted, and thus undertook to administer to others what had never been administered to them by themselves nor by others. Thus, after having laid down the dogma by some non-existent principle and private assumption, they proceeded to bestow upon others what they had not themselves received. The absurdity of this assumption is manifest from their own confession; for they admit that the uninitiated have not the power to baptize others. Now, according to their opinion, he who has not been baptized in conformity with their tradition is unbaptized as one not properly initiated, and they confirm this opinion by their practice, inasmuch as they rebaptize all those who join their sect, although previously initiated according to the tradition of the Catholic Church. These varying dogmas are the sources of innumerable troubles to religion; and many are deterred from embracing Christianity by the diversity of opinion which prevails in matters of doctrine.
The disputes daily became stronger, and, as in the beginning of heresies, they grew; for they had leaders who were not deficient in zeal or power of words; indeed, it appears that the greater part of the Catholic Church would have been subverted by this heresy, had it not found opponents in Basil and Gregory, the Cappadocians. The reign of Theodosius began a little while after; he banished the founders of heretical sects from the populous parts of the empire to the more desert regions.
But, lest those who read my history should be ignorant of the precise nature of the two heresies to which I have more especially alluded, I think it necessary to state that Aëtius, the Syrian, was the originator of the heresy usually attributed to Eunomius; and that, like Arius, he maintained that the Son is dissimilar from the Father, that He is a created being, and was created out of what had no previous existence. Those who held these views were formerly called Aëtians; but afterwards, during the reign of Constantius, when, as we have stated, some parties maintained that the Son is consubstantial with the Father, and others that He is like in substance to the Father, and when the council of Ariminum had decreed that the Son is only to be considered like unto the Father, Aëtius was condemned to banishment, as guilty of impiety and blasphemy against God. For some time subsequently his heresy seemed to have been suppressed; for neither any other man of note, nor even Eunomius, ventured openly upon undertaking its defense. But when Eunomius was raised to the church of Cyzicus in place of Eleusius, he could no longer quietly restrain himself, and in open debate he brought forward again the tenets of Aëtius. Hence, as it often happens that the names of the original founders of heretical sects pass into oblivion, the followers of Eunomius were designated by his own name, although he merely renewed the heresy of Aëtius, and promulgated it with greater boldness than was done by him who first handed it down.