*The division of the empire.* To each of the four rulers there was assigned a part of the empire as his particular administrative sphere. Diocletian took Thrace, Egypt and the Asiatic provinces, fixing his headquarters at Nicomedia. Maximian received Italy, Raetia, Spain and Africa, and took up his residence at Milan. To Galerius were allotted the Danubian provinces and the remainder of the Balkan peninsula, with Sirmium as his residence; while Constantius, to whose lot fell the provinces of Gaul, established himself at Trèves. However, this arrangement was not a fourfold division of the empire, for the Caesars were subject to the authority of the Augusti, and imperial edicts were issued in the name of all four rulers. Additional unity was given to the government by the personal ascendancy which Diocletian continued to maintain over his associates. One result of this arrangement was that Rome ceased to be the permanent imperial residence and capital of the empire, Milan and later Ravenna being preferred as the seat of government for the West. This change was largely the result of the exclusion of the Senate from all active participation in the government, and the fact that Rome retained traditions of republican and senatorial rule incompatible with the spirit of the new order. Yet, in spite of its loss of prestige, the Eternal City continued to hold a privileged status, and its citizens were fed and amused at the expense of the empire. *The restoration of the frontiers.* The division of the military authority among four able commanders enabled the government to deal energetically with all frontier wars or internal revolts. In 296 Constantius recovered Britain from Allectus, who three years previously had overthrown Carausius and proclaimed himself Augustus. In 297 Maximian was forced to appear in person in Africa to suppress a revolt of the Quinquegentiani. Meanwhile, Diocletian crushed a usurper named Achilles in Egypt and repulsed the invading Blemyes. Galerius, under the orders of Diocletian, after repelling attacks of the Iazyges (294 A. D.) and Carpi (296 A. D.), was called upon to meet a Persian invasion of Armenia and Mesopotamia. He was at first severely defeated, but, after being reinforced, won a decisive victory over Narses, the Persian king, and recovered Armenia. Diocletian himself won back Mesopotamia and the Persians were forced to acknowledge the Roman suzerainty over Armenia, while the Roman frontier in Mesopotamia was advanced to the upper Tigris. In all parts of the empire the border defenses were repaired and strengthened.