The most famous one issued the Edict of Milan and was written about by Eusebius.
One ruler by this name overcame the rebellion of Perbundus and was victorious at the naval Battle of Syllaeum. Another ruler of this name defeated his rival at the Battle of Chrysopolis, while yet another defeated Artabasdus early in his reign and was reportedly responsible for the death of Stephen the Younger. That emperor was the subject of a prophecy when Germanus witnessed him defecate in his baptismal font, and thus gained the nickname Copronymous. The most famous one issued the Edict of Milan and was written about by Eusebius. For ten points, give this name of the winner at the Battle of Milvian Bridge, the first Christian Roman emperor.
One ruler by this name overcame the rebellion of Perbundus and was victorious at the naval Battle of Syllaeum.
{Constantine}