More properly, an antipope from 351 to 358. Born in Rome, Italy; died in Porto, Italy, in 365. An archdeacon, he was consecrated by the heretical Acacius of Caesarea, when the legitimate pontiff, Liberius, was banished by the Emperor Constantius, an Arian. He was finally deposed by an order of the Roman Senate and the people. Many historians consider his election uncanonical.