Dionysius of Alexandria, on Rev 1:1

“The Revelation of Jesus Christ, which God gave unto him, to make known to his servants the things which must shortly come to pass: and signified, sending by his angel to his servant John,”

“What John this is, however, is uncertain. For he has not said, as he often does in the Gospel, that he is the disciple beloved by the Lord, or the one that leaned on His bosom, or the brother of James, or one that was privileged to see and hear the Lord. And surely he would have given us some of these indications if it had been his purpose to make himself clearly known. But of all this he offers us nothing; and he only calls himself our brother and companion, and the witness of Jesus, and one blessed with the seeing and hearing of these revelations. I am also of opinion that there were many persons of the same name with John the apostle, who by their love for him, and their admiration and emulation of him, and their desire to be loved by the Lord as he was loved, were induced to embrace also the same designation, just as we find many of the children of the faithful called by the names of Paul and Peter. There is, besides, another John mentioned in the Acts of the Apostles, with the surname Mark, whom Barnabas and Paul attached to themselves as companion, and of whom again it is said: "And they had also John to their minister." But whether this is the one who wrote the Revelation, I could not say. For it is not written that he came with them into Asia. But the writer says: "Now when Paul and his company loosed from Paphos, they came to Perga in Pamphylia: and John, departing from them, returned to Jerusalem." I think, therefore, that it was some other one of those who were in Asia. For it is said that there were two monuments in Ephesus, and that each of these bears the name of John.”

Imported from an open dataset — not yet checked against the printed edition.