John III was pope from 561 to 574. A Roman surnamed Catelinus, he was of a distinguished family, being the son of one Anastasius who bore the title of illustris. Although John reigned nearly thirteen years very little is known of his pontificate. It fell during the stormy times of the Lombard invasion, and practically all the records of his reign have been destroyed. It is recorded in the Liber Pontificalis that he died on July 7, 574.

Preceded by:
Pope Pelagius I
List of popes Succeeded by:
Pope Benedict I