Sylvester I (bust depicted), during whose pontificate many churches in Rome were constructed by Constantine the Great, began his reign as pope. Pope Sylvester I: Pope Sylvester I was the bishop of Rome from 31 January 314 until his death on 31 December 335. He filled the See of Rome at an important era in the history of the Western Church, though very little is known of his life. January 31, 314. Wiki link