It must not be overlooked, however, that there were other reasons for withholding the unqualified title of Roman Empire from the Eastern dominions. The chief of these is that the court of Constantinople departed very radically from the traditions of the West, taking on oriental manners and customs, and, what is most remarkable, gradually relinquishing the Latin speech and substituting for it the language of Greece. We have seen in our studies of earlier Roman history the marked tendency to the Hellenisation of Rome through the introduction of Greek culture from the time when the Roman Republic effected the final overthrow of Greece. It will be recalled that some of the most important histories of Rome, notably those of Polybius and Appian and Dionysius and Dion Cassius, were written in Greek. The emperor Marcus Aurelius wrote his _Meditations_ in the same language. But this merely represented the tendency of the learned world. There was no propensity to substitute Greek for Latin as the language of everyday life so long as the seat of empire remained in the West. Now, however, as has been intimated, this strange substitution was effected; the writers of this Later Roman Empire in the East looked exclusively to classical Greece for their models, and in due course the language of court and of common people alike came to be Greek also, somewhat modified from the ancient idiom with the sweep of time, but in its essentials the same language which was spoken at Athens in the time of Pericles. Obviously there is a certain propriety in this use of the term Greek Empire as applied to a principality whose territory included the ancient realms of Athens, and whose customs and habits and speech thus preserved the traditions of ancient Hellas. The use of the terms Eastern Empire and Byzantine Empire requires no elucidation, having an obvious propriety. As has been said, we shall find it convenient here to employ one or another of the four terms indiscriminately; giving preference perhaps, if a choice must be made, to the simplest and most non-committal form, Eastern Empire. By whatever name designated, the principality whose fortunes we are to follow will hold our interest throughout a period of more than a thousand years, from the death of Theodosius in 395 to the final overthrow of Constantinople in 1456. This period is almost exactly coincident with the epoch pretty generally designated by historians as the Middle Ages, and usually estimated as a time of intellectual decadence.