One of the many tragedies of Christian history is that the Papacy, which ought to be a source of unity, has so often been a point of division; indeed, what often began as internal quarrels have, too often, turned into a source of schism.

I was asked recently why, if he was such an important figure, St Peter failed to inform us of his unique position? Good question, to which the answer is clear – it was all there in Matthew’s Gospel. In his own letters, Peter is content to appeal to Apostolic authority and eye-witness testimony. But it is important to understand that just like the doctrines and dogma we have been examining lately, the position of the Pope developed.  We have been examining how the early Christians developed their understanding of the nature of Christ, and of the Trinity, so it should come as no surprise that the same was true when it came to the office of the Pope.

So, just as with the Trinity, the natures of Christ, and the Theotokos, so too with the purpose of the promise given to Peter; these things the Church worked out as it came to have need of them. We cannot know why Jesus did not just write everything down in a book, but he did not; he founded a Church. Justr as it was left to that Church to tell us what the Canon of Scripture was, so it was left to it to work out the implications of the Petrine promise in Matthew’s Gospel.

It has been, then, only as problems arose in certain areas that the Church has come to need to define things. That is as true of the Papacy as anything else. A ‘primacy of honour’ was always acknowledged, but working out what it meant in practice was not easy, as successive posts here tried to show.

It is clear that of the five ancient Patriarchal Sees, the three most important were Rome, Alexandria and Constantinople. It is interesting that the two cities where we know from Scripture that Peter lived, Jerusalem and Antioch, never mounted the sort of claims made by Rome, where tradition has it that Peter was martyred, and where his tomb can be seen. Alexandria, as befitted the See of St Mark (the interpreter of Peter) never questioned Rome’s primacy; that was reserved for Constantinople, whose claims were to be second to Rome, and were based entirely on its position as the imperial capital.

We have seen that Leo was basing his claims for the powers of his office on Peter’s position as the leader of the Apostles, and that that had nothing to do with Rome being an imperial city; the oft-touted notion that Roman Catholicism was ‘Roman State run religion’ (to quote Bosco) could not be wider of the mark; it had nothing to do with the Roman empire, and everything to do with trying to establish a position for the Church which made it as independent of State control as possible. For 1000 years after the death of St Leo the Great, Popes struggled to assert their independence from State control.

The greatest boost to the understanding of the development of the position of the Papacy came with the expansion of Islam: with Jerusalem, Antioch and Alexandria all under Muslim control by the end of the sixth century, only Rome and Constantinople were left; after 1453 there was only Rome. The need for some central authority to pronounce with authority on vexing matters of doctrine and dogma did not end with the fall of the other Patriarchal Sees, and Rome found itself in a situation where it was the last one standing. The question of whether Rome has always used its position wisely is an open one, and it would be hard to say the answer was yes. But that is quite separate from the developing understanding of the office, which held that in matters of faith and doctrine the Pope was protected from error.