Christianity emerged in the 1st century as one of many new religions in the Roman Empire. Early Christians were persecuted as early as 64 A.D. when Nero ordered large numbers of Christians executed in retaliation for the Great Fire of Rome. Christianity remained a minority religion in the empire for several centuries climaxing in the repression of Galerius in 303. Following Constantine the Great's victory on Milvian Bridge, which he attributed to a Christian omen he saw in the sky, the Edict of Milan declared that the empire would no longer sanction persecution of Christians. Following Constantine's deathbed conversion in 337 all emperors adopted Christianity, except for Julian the Apostate who, during his brief reign, attempted unsuccessfully to re-instate paganism.