The Roman Empire is the governmental successor to the Roman Republic, both in the muggle and in the Wizarding world. It was first established by Octavian Caesar Augustus, who would not only be the first person to possess the mantle of the Universal Monarchy since the fall of Atlantis millennia ago, but also be the first person to be the mortal and physical incarnation of Aernus since the deaths of the Sacred Triumvirate of Atlantis.