The Roman Empire, also referred to in a derogatory fashion as the Byzantine Empire, was the successor state to the Roman Republic, both to the muggles and the wizarding community. It was first established by Octavian Caesar Augustus, who would become the first person to possess the mantle of the universal monarchy since the fall of the Atlantean Empire millenia ago. It has its capital as Constantinople, which is located in the Bosphorus Cavern, under its muggle counterpart of the same name, and while there is no official state religion, the religion with most adherents is Aeneanism.