Italy had thus been mapped out afresh; what was done with Italy in the time of Augustus was done with the whole Empire in the time of Constantine. What Italy was in the earlier time the whole Empire was in the later; the old distinctions had been wiped out, and the whole of the Roman world stood ready to be parted out into fresh divisions. Under Diocletian, the Empire was divided into four parts, forming the realms of the four Imperial colleagues of his system, the two Augusti and their subordinate Cæsars. ♦Division of the Empire under Diocletian. A.D. 292.♦ Diocletian’s system of government involved a practical degradation of Rome from the headship of the Empire. Augusti and Cæsars now dwelled at points where their presence was more needed to ward off Persian and German attacks from the frontiers; Rome was forsaken for Nikomêdeia and Milan, for Antioch, York, and Trier. ♦Reunion under Constantine. A.D. 323. | Division between the sons of Theodosius. A.D. 395.♦ The division between the four Imperial colleagues lasted under another form after the Empire was re-united under Constantine, and it formed the groundwork of the more lasting division of the Empire into East and West, between the sons of Theodosius. The whole Empire was now mapped out according to a scheme in which ancient geographical names were largely preserved, but in which they were for the most part used in new or, at least, extended meanings. ♦The Four Prætorian Prefectures.♦ The Empire was divided into four great divisions called Prætorian _Prefectures_. These were divided into _Dioceses_—a name used in this nomenclature without regard to the ecclesiastical sense which was borrowed from it—and the dioceses again into _Provinces_. The four great prefectures of the _East_, _Illyricum_, _Italy_, and _Gaul_, answer nearly to the fourfold division under Diocletian; while we may say that, in the final division, Illyricum and the East formed the Eastern Empire, and Italy and Gaul formed the Western. But it is only roughly that either the prefectures or their smaller divisions answer to any of the great national or geographical landmarks of earlier times. ♦Prefecture of the East.♦ The Prefecture of the _East_ is that one among the four which least answers to anything in earlier geography, natural or historical. Its boundaries do not answer to those of any earlier dominion, nor yet to any great division of race or language. It stretched into all the three continents of the old world, and took in all those parts of the Empire which were never fully brought under either Greek or Roman influences. But it also took in large tracts which we have learned to look on as part of the Hellenic world—not only lands which had been, to a great extent, Hellenized in later times, but even some of the earliest Greek colonies. The four dioceses into which the Prefecture was divided formed far more natural divisions than the Prefecture itself. ♦Dioceses of the East,♦