All I'm saying is that if the original homeland of an empire was overrun by the forces a foreign nation, then a new seat of government would be chosen if enough of its territories remained under its authority. I know that the Imperium Romanorum was continually divided and reunited before the reigns of Honorius and Arcadius. And even King Theodoric of the Ostrogoths rule of Italy on behalf of Emperor Zeno was a pretense of legality.