Having seen a vision of the Flaming Cross in the sky at noon, Constantine won a key victory over his rival at Tiber River's Mulvius Bridge 10-28-312. He became a Christian, granting toleration to the religion in the edict of Milan (313). From his victory at Chrysopolis (09-18-323) he ruled both the eastern and western Roman empires. He presided as sole emperor at the Council of Nicaea (325). He laid the foundation of the city of Constantinople in 326, establishing the imperial capital there; he was inaugurated there 05-11-330 as the city was dedicated to the Blessed Virgin. Christianity had become the state religion. Constantine was declared "Emperor" in 306 A.D. at Eboracum, now York, England. --Compton's on-line Encyclopedia, America On-Line, 5/95: