I am a Catholic that is in full communion with the Bishop of Rome.
Cyprian of Carthage (c. A.D. 253):
" . . . [the heretics] dare even to set sail . . . to the chair of Peter and the principal Church [at Rome], in which sacerdotal unity has its source . . . whose faith was praised by the preaching Apostle, and among whom it is not possible for errors of faith [heresy] to have entrance” [Letters 59 (55), 14)].
Maximus the Confessor (c. A.D. 650):
“. . . [the Apostolic See of Rome] from God the Incarnate Word Himself as well as all the holy Councils, according to the sacred canons and definitions, has received and possesses supreme power in all things and for all things, over all the holy churches of God throughout the world, as well as power and authority of binding and loosing. For with this church, the Word, who commands the powers of heaven, binds and looses in heaven. For if he thinks he must satisfy others, and fails to implore the most blessed Roman Pope, he is acting like a man who, when accused of murder or some other crime, does not hasten to prove his innocence to the judge appointed by law, but only uselessly and without profit does his best to demonstrate his innocence to private individuals, who have no power to acquit him from the accusation. . . .” [Opuscula 12, Patrologia Graeca 91.141-146].
Mar Abdisho of Soba (c. A.D. 1318):
“To the great Rome [authority] was given because the two pillars are laid in the grave there, Peter, I say, the head of the Apostles, and Paul, the teacher of the nations. [Rome] is the first see and the head of the patriarchs” [Memra; Risha 1].
“…And as the patriarch has authority to do all he wishes in a fitting manner in such things as are beneath his authority, so the patriarch of Rome has authority over all patriarchs, like the blessed Peter over all the community, for he who is in Rome also keeps the office of Peter in all the Church. He who transgresses against these things the ecumenical synod places under anathema” [Memra 9; Risha 8].