The Edict of Milan, issued in 313 CE, is the law that ordered religious toleration in the Roman Empire. This edict was a joint proclamation by the Roman emperors Constantine I and Licinius.
The significance of the Edict of Milan lies in its granting of freedom of worship to all religions, effectively ending the persecution of Christians that had been prevalent in the empire. It allowed Christians to practice their faith openly and return to confiscated properties.
This change was pivotal for the spread of Christianity, as it not only legalized the faith but also paved the way for it to become the dominant religion in the Roman Empire. The Edict of Milan marked a turning point in religious history, illustrating the shift from a pagan Roman state to one that recognized and accepted Christianity as a legitimate and sanctioned religion.