But whether this Eastern principality should properly be spoken of as the Later Roman Empire, or as the Eastern, Byzantine, or Greek Empire, is, as has been suggested, a moot point among historians. The difficulty is perhaps met to the best advantage if we disregard the controversial aspects of the question and make free use of each and all of these names; indeed, in so doing, convenience joins hands with logicality. The empire of Arcadius and his immediate successors was certainly entitled to be called the Roman Empire quite as fully as, for example, were the dominions of Diocletian and Constantine. There was no sudden breach of continuity, no thought of entrance upon a new epoch with the accession of Arcadius. It was no new thing that power was divided, and that there should be two capitals, one in the East and one in the West. On the contrary, as we have seen, there had been not merely a twofold but a fourfold division of power most of the time since the day of Diocletian. No contemporary could have predicted that after the death of Theodosius the Roman dominions in the East and in the West would never again be firmly united under a single head. Nor indeed is it quite true that the division was complete and permanent; for, as we shall see, there were to be rulers like Justinian and Zeno who had a dominating influence over the Western territories, and who regarded themselves as masters of the entire Roman domain. And even when the division became complete and permanent, as it scarcely did before the time of Charlemagne, it could still be fairly held that the Roman Empire continued to exist with its sole capital at Constantinople, whither Constantine had transferred the seat of power, regardless of the fact that the Western dominion had been severed from the empire. The fact that this Western dominion included the city of Rome itself, which had given its name to the empire, and hence seemed indissoluble from it, is the chief reason for the seeming incongruity of applying the term Later Roman Empire to the dominion of the East.