Pope John I

John came from Siena and became bishop of Rome in August 523. In 525 he worked with the monk Dionysius Exiguus to standardize how the Western Church calculated Easter's date. Theoderic, the Ostrogoth king, dispatched him to Constantinople to negotiate better treatment for Arians. John managed some success, but when he returned to Ravenna, Theoderic had him imprisoned on charges of conspiring with the eastern capital. Frail and poorly treated, the pope died in custody on 18 May 526.