Editing Tetrarchy (section)

==Legacy==
[[File:Raphael-Constantine at Milvian Bridge.jpg|thumb|200px|''Constantine at the [[battle of the Milvian Bridge]]'', fresco by [[Raphael]], Vatican Rooms.]]
Although the tetrarchic system as such only lasted until 313, many aspects of it survived. The fourfold regional division of the empire continued in the form of [[Praetorian prefecture]]s, each of which was overseen by a [[praetorian prefect]] and subdivided into administrative [[Roman diocese|dioceses]], and often reappeared in the title of the military supra-provincial command assigned to a ''[[magister militum]]''.

The pre-existing notion of ''[[consortium imperii]]'', the sharing of imperial power, and the notion that an associate to the throne was the designated successor (possibly conflicting with the notion of hereditary claim by birth or adoption), was to reappear repeatedly.

The idea of the two halves, the east and the west, re-emerged and eventually resulted in the permanent de facto division into two separate Roman empires after the death of [[Theodosius I]]; though, importantly, the Empire was never formally divided. The emperors of the eastern and western halves legally ruled as one imperial college until the [[Fall of the Western Roman Empire]] left Byzantium, the "second Rome", as the sole direct heir.