Constantine (February 27, 272–May 22, 337), commonly known as Constantine I or Constantine the Great, was proclaimed Augustus by his troops on July 25, 306 and ruled an ever-growing portion of the Roman Empire until his death. Constantine is famed for his refounding of Byzantium (modern Istanbul) as "Nova Roma" (New Rome), which was popularly known in his time as "Constantine's City"— (Constantinopolis, Constantinople). Constantine is best remembered in modern times for the Edict of Milan in 313 and the First Council of Nicaea in 325, which fully legalized and then legitimized Christianity in the Empire for the first time. These actions are considered major factors in that religion's spread, and his reputation as the "first Christian Emperor" has been promulgated by historians from Lactantius and Eusebius of Caesarea to the present day.

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