Who was the first Christian Roman Emperor? (r. 306-337 AD)

Constantine I is considered the first Christian Roman emperor. After reportedly seeing a vision before the Battle of the Milvian Bridge (312), he favored Christianity and issued the Edict of Milan (313), granting religious tolerance across the empire. He also convened the Council of Nicaea (325), shaping core Christian doctrine, and founded Constantinople, which became a Christian imperial capital. Though baptized late in life, his policies decisively advanced Christianity’s status in Rome. Remember the others: Diocletian launched the Great Persecution; Maxentius was Constantine’s rival defeated at the Milvian Bridge; Julian II, nicknamed “the Apostate,” tried to revive paganism. Mnemonic: “Constantine made Christianity constant in the Empire.”