Alinari/Art Resource, NY

The canonical view. Jesus designates his successors by giving the key to the church to Peter (carrying a cross, to Jesus’ left) and the scroll of the Law of the New Covenant to Paul (to Jesus’ right). Four other apostles stand in attendance on this sixth-century marble sarcophagus from Sant’Apollinare in Classe, near Ravenna, Italy.

In Matthew 16:18–19, Jesus states: “You are Peter, and on this rock (Greek, petros) I will build my church…I will give you the keys of the kingdom of heaven.” Paul is shown receiving the New Law because he was one of its most active advocates.

The succession may not have been as smooth as suggested in the New Testament (and this relief), however. In noncanonical gospels, Peter, Mary Magdalene, Thomas and James are all presented as Jesus’ second-in-command.