“The Lord says to Peter: ‘I say to you,’ he says, ‘that you are Peter, and upon this Rock I will build my Church, and the gates of Hell will not overcome it. And to you I will give the keys of the kingdom of Heaven; and whatever things you bind on earth shall be bound also in Heaven, and whatever you loose on earth, they shall be loosed also in Heaven’ [Matt. 16:18–19]). … On him [Peter] he builds the Church, and to him he gives the command to feed the sheep [John 21:17], and although he assigns a like power to all the apostles, yet he founded a single Chair [Cathedra], and he established by his own Authority a source and an intrinsic reason for that Unity. Indeed, the others were also what Peter was [i.e., Apostles], but a Primacy is given to Peter, whereby it is made clear that there is but one Church and one Chair. So too, all [the Apostles] are shepherds, and the flock is shown to be One, fed by all the Apostles in single-minded accord. If someone does not hold fast to this Unity of Peter, can he imagine that he still holds the Faith? If he [should] desert the Chair of Peter upon whom the Church was built, can he still be confident that he is in the Church?” (The Unity of the Catholic Church 4; 1st edition [A.D. 245]). - Saint Cyprian, Martyr, Bishop of Carthage in Africa
“I follow no Leader but Christ and join in Communion with none but your Blessedness [Pope Damasus I], that is, with the Chair of Peter. I know that this is the Rock on which the Church has been built. Whoever eats the Lamb outside this House is profane. Anyone who is not in the Ark of Noah (i.e., the Barque of Peter) will perish when the flood prevails” (Letters 15:1 [A.D. 395]). - Saint Jerome, ordained Priest in Antioch, Syria; dwelt in Constantinople for a time; dear friend of Saint Gregory of Nazianzus, Bishop of Nazianzus
“Philip the Presbyter and legate of the Apostolic See said: ‘There is no doubt, and in fact it has been known in all ages, that the holy and most blessed Peter, prince and head of the apostles, pillar of the faith, and foundation of the Catholic Church, received the keys of the kingdom from our Lord Jesus Christ, the Savior and Redeemer of the human race, and that to him was given the power of loosing and binding sins: who down even to today and forever both lives and judges in his successors. The holy and most blessed Pope Celestine, according to due order, is his successor and holds his place, and us he sent to supply his place in this holy Synod’” (Acts of the Council, session 3 [A.D. 431]). - From the Sacred and Ecumenical Council of Ephesus
"In the first year (A.D. 715) of his (Pope St. Gregory II) Pontificate, he received a letter from John, Patriarch of Constantinople. Addressed "To the Sacred Head of the Church", it was really an apology for his having shown himself subservient to Philippieus Bardanes in the matter of Monothelism." - Catholic Encyclopedia of 1918, Article on Pope Saint Gregory II
Doesn't that kind of sum it up?
I mean really, we've got developed and orthodox Papal theology, so explicit as to talk about the Chair of Peter as being the intrinsic reason for the Unity of the Catholic Church, in the third century by a venerable African Father and Martyr. Down the line of history in the fourth, fifth, and eighth century, same exact teaching, simply more developed in orthodox understanding. This is no mere Primacy of Honor, this is a Primacy of Judgment, necessary Communion, and Sacred Headship as Christ's Vicar. This is a Primacy necessary to the very constitution of the Church. And that is why I'm Catholic.
Glory to Jesus Christ! Glory to Him forever!
So echoing Saint Jerome, I say, I follow no leader but Christ the King, and I join in Communion with none but your Blessedness, Pope Benedict XVI, that is, with the Chair of Peter.