Jerome’s commentary on Titus 1:5 contains an important testimony about the development of the monoepiscopacy in the early church (in addition to various statements in his letters). Since this passage is not found easily in its entirety online, I want to produce it here for public record, as a supplement to my video on the topic (see my video below):
“It is therefore the very same priest, who is a bishop, and before there existed men who are slanderers by instinct, [before] factions in the religion, and [before] it was said to the people, “I am of Paul, I am of Apollos, but I am of Cephas,” the churches were governed by a common council of the priests. But after each one began think that those whom he had baptized were his own and not Christ’s, it was decreed for the whole world that one of the priests should be elected to preside over the others, to whom the entire care of the church should pertain, and the seeds of schism would be removed.
If someone thinks that this is our opinion, but not that of the Scriptures—that bishop and priest are one, and that one is the title of age, the other of his duty—let him reread the apostle’s words to the Philippians when he says, “Paul and Timothy, slaves of Jesus Christ, to all the saints in Christ Jesus who are in Philippi, with the bishops and deacons, grace to you and peace,” and so on. Philippi is a single city in Macedonia, and at least in one city several were not able to be bishops, as they are now thought. But because at that time they called the same men bishops whom they also called priests, therefore he has spoken indifferently of bishops as if of priests.
This may still seem doubtful to someone unless it is proven by another testimony. In the Acts of the Apostles it is written that when the apostle came to Miletus, he sent to Ephesus and summoned the priests of that church to whom later he said among other things, “Watch yourselves, and the whole flock in which the Holy Spirit appointed you bishops to feed the church of God, which he acquired through his own blood.” And observe here very carefully how, by summoning the priests of the single city of Ephesus, later he has spoken of the same men as bishops.
If anyone wants to receive that epistle which is written in Paul’s name to the Hebrews, even there care for the church is shared equally by many. For indeed he writes to the people, “Obey your leaders, and be in subjection; for they are the ones who watch over your souls, as those who will give a reckoning. Let them not do this with sighing; for indeed this is advantageous to you.” And Peter, who received his name from the firmness of his faith, speaks in his own epistle and says, “As a fellow priest, then, I plead with the priests among you, and as a witness of Christ’s sufferings, I who am a companion also of his glory that is to be revealed in the future, tend the Lord’s flock that is among you, not as though by compulsion but voluntarily.”
These things [have been said] in order to show that to the men of old the same men who were the priests were also the bishops; but gradually, as the seed beds of dissensions were eradicated, all solicitude was conferred on one man. Therefore, just as the priests know that by the custom of the church they are subject to the one who was previously appointed over them, so the bishops know that they, more by custom than by the truth of the Lord’s arrangement, are greater than the priests. And they ought to rule the Church commonly, in imitation of Moses who, when he had under his authority to preside alone over the people of Israel, he chose the seventy by whom he could judge the people.”
St. Jerome’s Commentaries on Galatians, Titus, and Philemon, trans. Thomas P. Scheck (University of Notre Dame Press, 2010), 289-290).