Catholics believe that the bishop of Rome inherits the mantle of Peter, apostle of Jesus Christ who was entrusted with the administration of his church after he died. Peter travelled to Rome where he is believed to have established a Christian community before he was martyred. All popes are, then, successors of Peter not only as leading the Christian community in Rome, but also as leading the Christian community in general, and they maintain a direct connection to the original apostles.
Peters position as leader of the Christian church is traced back to the Gospel of Matthew:
- And I say also unto thee, That thou art Peter, and upon this rock I will build my church; and the gates of hell shall not prevail against it. And I will give unto thee the keys of the kingdom of heaven: and whatsoever thou shalt bind on earth shall be bound in heaven: and whatsoever thou shalt loose on earth shall be loosed in heaven.
(Matthew 16: 18-19)
Based upon this Catholics have developed the doctrine of papal primacy, the idea that as successor to Peter, the pope is the head of the worldwide Christian Church. Although principally the bishop of Rome, he is much more than just first among equals, he is also the living symbol of the unity of Christianity.
Even if we accept the tradition that Peter was martyred in Rome, however, there is no direct evidence for his having established the Christian church there. It is likely that Christianity appeared in Rome some time during the 40s, about two decades before Peter would have arrived. That Peter founded the Christian church in Rome is more of a pious legend than historical fact, and the connection between Peter and bishop of Rome was not even made explicit by the Church until the reign of Leo I during the fifth century.
There isnt even any evidence that, once Peter was in Rome, he functioned as any sort of administrative or theological leader certainly not as a bishop in the way we understand the term today. All available evidence points to the existence not of a monoepiscopal structure but instead to committees of elders (presbyteroi) or overseers (episkopoi). This was standard in Christian communities all over the Roman empire.
Not until a couple of decades into the second century do letters from Ignatius of Antioch describe churches led by a single bishop who was merely assisted by the presbyters and deacons. Even once a single bishop can definitively be identified in Rome, though, his powers were not at all like what we see in the pope today. The bishop of Rome didnt call councils, didnt issue encyclicals, and wasnt sought after to resolve disputes about the nature of Christian faith.
Finally, the position of the bishop of Rome was not regarded as significantly different from the bishops of Antioch or Jerusalem. Insofar as the bishop of Rome was accorded any special status, it was more as a mediator than as a ruler. People appealed to the bishop of Rome to help mediate disputes arising over issues like Gnosticism, not to deliver a definitive statement of Christian orthodoxy. Quite a long time went by before the Roman church would actively and on its own interfere in other churches.
If there is little or no evidence linking Peter with the establishment of the Christian church in Rome, then how and why did Rome become the central church in early Christianity? Why wasnt the wider Christian community centered on Jerusalem, Antioch, Athens, or other major cities closer to where Christianity got its start?
Actually it would have been surprising if the Roman church hadnt taken on a leading role it was, after all, the political center of the Roman empire. Large numbers of people, especially influential people, lived in and around Rome. Large numbers of people were always passing through Rome on political, diplomatic, cultural, and commercial ventures.
Its only natural that a Christian community would have been established here early on and that this community would have ended up including a number of important people. At the same time, though, the Roman church did not by any means rule over Christianity in general, not in the way that the Vatican rules over Catholic churches today. Currently the pope is treated as if he were not merely the bishop of the Roman church, but rather the bishop of every church while the local bishops are merely his assistants. The situation was radically different during the first centuries of Christianity.