St. Peter's Basilica, which is called "Basilica di San Pietro in Vaticano" in Italian, is a large church in the Vatican City, in Rome, Italy. It is often called "the greatest church in Christendom". In Catholic tradition, St. Peter's Basilica is believed to be the burial place of Saint Peter, who was one of the twelve apostles of Jesus. It is believed that Saint Peter was the first Bishop of Rome.