 There, through the treachery of the governor, Gratian was delivered over to one of the rebel generals, Andragathius, and assassinated on 25 August 383.The reign of Gratian forms an important epoch in church history, since during that period Nicene Christianity for the first time became dominant throughout the empire.In his reign, his co-Emperor Theodosius I also published an edict that all their subjects should profess the faith of the bishops of Rome and Alexandria (i.e., the Nicene faith).