Saint Peter. Engraving attributed to C. Cort.

A fisherman on the lake of Genezareth in Galilee, Saint Peter was, with his brother Andrew, the first of the Apostles. His name was Simon; he was renamed Peter (Kephas in Aramaic, Petros in Greek) by Jesus to indicate that he would be the cornerstone (petra) of the Church. Often depicted with one or two keys, representing his role as gatekeeper of heaven. In the Middle Ages he was invoked against fevers, bouts of madness and snake-bite.