Those who say that the practice developed in the East in the 600s are also incorrect, because the Oriental Churches, which split in the 400s, such as the Copts, the Armenians, and the Syrians, also practice a married, non-celibate priesthood, as do the Assyrian Apostolic Christians, who split even earlier.
Thus
Eusebius declares that it is befitting that priests and those occupied in the ministry should observe continence (Demonst. Evangel., I, C. ix), and St. Cyril of Jerusalem urges that the minister of the altar who serves
God properly holds himself aloof from women (Cat. xii, 25). St. Jerome further seems to speak of a custom generally observed when he declares that clerics, “even though they may have wives, cease to be husbands”.
But the passage most confidently appealed to is one of St. Epiphanius where the holy doctor first of all speaks of the accepted ecclesiastical rule of the priesthood (
kanona tes ierosynes) as something established by the Apostles (Haer., xlviii, 9), and then in a later passage seems to describe this rule or canon in some detail. “Holy Church”, he says, “respects the dignity of the priesthood to such a point that
she does not admit to the diaconate, the priesthood, or the episcopate, no nor even to the subdiaconate, anyone still living in marriage and begetting children. She accepts only him who if married gives up his wife or has lost her by death, especially in those places where the ecclesiastical cannons are strictly attended to” (Haer., lix, 4). Epiphanius goes on, however, to explain that there are localities in which priests and
deacons continue to have children, but he argues against the practice as most unbecoming and urges that the Church under the guidance of the Holy Ghost has always in the past shown her disapproval of such procedure. But we need hardly insist that all this is very inadequate evidence (even when supplemented by some few citations from St. Ephraem and other Orientals) to support the contention that a general rule of celibacy existed from Apostolic times. Writers in the fourth century were prone to describe many practices (e.g. the
Lenten fast of forty days) as of Apostolic institution which certainly had no claim to be so regarded. On the other hand, there are facts which tell the other way. The statement of Clement of Alexandria at an earlier date is open to no ambiguity. After commenting on the texts of St. Paul noted above, and expressing his veneration for a life of chastity, Clement adds: “All the same, the Church fully receives the husband of one wife whether he be priest or
deacon or layman, supposing always that he uses his marriage blamelessly, and such a one shall be saved in the begetting of children” (Stromateiae, III, xiii). Not less explicit is the testimony given by the church historian, Socrates. He declares that in the Eastern Churches neither priests nor even bishops were bound to separate from their wives, though he recognized that a different custom obtained in Thessaly and in Greece (H.E., Bk. I, cap. xi) Socrates tells the story of Paphnutius rising in the assembly and objecting to an enactment which he considered to rigorous in behalf of celibacy. It would be sufficient, he thought, that such as had previously entered on their sacred calling should abjure matrimony according to the ancient tradition of the Church, but that none should be separated from her to whom, while yet unordained, he had been united. And these sentiments he expressed although himself without experience of marriage. Some attempt has been made to discredit this story, but nearly all modern scholars (notably Bishop von Hefele, with his most recent editor, Dom H. Leclercq) accept it without reserve. The fact that the attitude of Bishop Paphnutius differs but little from the existing practice of the Eastern Churches is alone a strong point in its favour. These testimonies, it will be observed, are from
Eastern sources and indicate, no doubt, the prevailing Oriental discipline. Wernz expressed the opinion that from the earliest days of the Church the custom, if not the law, was for bishops, priests, and all in major orders, to observe celibacy.
newadvent.org/cathen/03481a.htm
“Celibacy” in this case means, abstaining from sex. By the time of Nicea, both East and West had the same practice, married priests must abstain.