In 313 emperor Constantine of Rome issued the Edict of Milan, mandating tolerance for all religions. The correct option to the given question is the last option. He was also known by the name Saint Constantine. He was the emperor of Rome from 306 BC to 337 BC. He was the son of a great Roman army officer by the name of Flavius Valerius Constantius. Constantine I was responsible for several social and political changes that led to the strengthening of the Roman empire. He was the one that introduced a new gold coin by the name of Solidus for fighting inflation.