But you cannot deny that you know that the episcopal seat was established first in the city of Rome by Peter and that in it sat Peter, the head of all the apostles, wherefore he is called Cephas, the one chair in which unity is maintained by all. Neither do other Apostles proceed individually on their own; and anyone who would set up another chair in opposition to that single chair would, by that very fact, be a schismatic and a sinner. It was Peter, then, who first occupied that chair, the foremost of his endowed gifts …. I but ask you to recall the origins of your chair, you who wish to claim for yourselves the title of holy Church.

Optatus of Mileis