Saint Peter (Greek Petros, "rock") was the most prominent of the Twelve Apostles whom Jesus chose as his original disciples. His life is prominently featured in the New Testament Gospels and the Acts of the Apostles. Peter was a Galilean fisherman assigned a leadership role by Jesus (Matthew 16:18; John 21:15–16). He was with Jesus during events witnessed by only a few apostles, such as the Transfiguration. Early Christian writers provided more details about his life and asserted his primacy. Tradition describes him as the first bishop of Rome, the author of two canonical epistles, and a martyr under Nero, crucified head down and buried in Rome. His memoirs are traditionally cited as the source of the Gospel of Mark.

The Roman Catholic Church, Eastern Orthodox, Oriental Orthodox and Anglican Communion, consider Simon Peter a saint. Roman Catholics regard the Pope as Peter's successor and therefore the rightful superior of all other bishops. Eastern and Oriental Orthodox also recognise the Bishop of Rome as the successor Saint Peter and the Ecumenical Patriarch sends a delegation each year to Rome to participate in the celebration of his feast. In the "Ravenna Document" of 13 October 2007, the representatives of the Eastern Orthodox Church agreed that "Rome, as the Church that 'presides in love' according to the phrase of St Ignatius of Antioch (To the Romans, Prologue), occupied the first place in the taxis, and that the bishop of Rome was therefore the protos among the patriarchs. They disagree, however, on the interpretation of the historical evidence from this era regarding the prerogatives of the bishop of Rome as protos, a matter that was already understood in different ways in the first millennium."

The historical accuracy of the accounts of Peter's role in Rome is a matter of ongoing debate.

In art, he is often depicted holding the keys to the kingdom of heaven (interpreted by Roman Catholics as the sign of his primacy over the Church), a reference to Matthew 16:19.