After the conciliation of the Goths,--for we cannot call it the conquest,--Theodosius was obliged to turn his attention to the affairs of the Western Empire; for he ruled only the Eastern provinces. It would seem that Gratian, who had called him to his assistance to preserve the East from the barbarians, was now in trouble in the West. He had not fulfilled the great expectation that had been formed of him. He degraded himself in the eyes of the Romans by his absorbing passion for the pleasures of the chase; while public affairs imperatively demanded his attention. He received a body of Alans into the military and domestic service of the palace. He was indolent and pleasure-seeking, but was awakened from his inglorious sports by a revolt in Britain. Maximus, a native of Spain and governor of the island, had been proclaimed emperor by his soldiers. He invaded Gaul with a large fleet and army, followed by the youth of Britain, and was received with acclamations by the armies of that province. Gratian, then residing in Paris, fled to Lyons, deserted by his troops, and was assassinated by the orders of Maximus. The usurper was now acknowledged by the Western provinces as emperor, and was too powerful to be resisted at that time by Theodosius, who accepted his ambassadors, and made a treaty with the usurper by which he was permitted to reign over Britain, Gaul, and Spain, provided that the other Western provinces, including Wales, should accept and acknowledge Valentinian, the brother of the murdered Gratian, who was however a mere boy, and was ruled by his mother Justina, an Arian,--that celebrated woman who quarrelled with Ambrose, archbishop of Milan. Valentinian was even more feeble than Gratian, and Maximus, not contented with the sovereignty of the three most important provinces of the Empire, resolved to reign over the entire West. Theodosius, who had dissembled his anger and waited for opportunity, now advanced to the relief of Valentinian, who had been obliged to fly from Milan,--the seat of his power. But in two months Theodosius subdued his rival, who fled to Italy, only, however, to be dragged from the throne and executed.
Having terminated the civil war, and after a short residence in Milan, Theodosius made his triumphal entry into the ancient capital of the world. He was now the absolute and undisputed master of the East and the West, as Constantine had been, whom he resembled in his military genius and executive ability; but he gave to Valentinian (a youth of twenty, murdered a few months after) the provinces of Italy and Illyria, and intrusted Gaul to the care of Arbogastes,--a gallant soldier among the Franks, who, like Maximus, aspired to reign. But power was dearer to the valiant Frank than a name; and he made his creature, the rhetorician Eugenius, the nominal emperor of the West. Hence another civil war; but this more serious than the last, and for which Theodosius was obliged to make two years' preparation. The contest was desperate. Victory at one time seemed even to be on the side of Arbogastes: Theodosius was obliged to retire to the hills on the confines of Italy, apparently subdued, when, in the utmost extremity of danger, a desertion of troops from the army of the triumphant barbarian again gave him the advantage, and the bloody and desperate battle on the banks of the Frigidus re-established Theodosius as the supreme ruler of the world. Both Arbogastes and Eugenius were slain, and the East and West were once more and for the last time united. The division of the Empire under Diocletian had not proved a wise policy, but was perhaps necessary; since only a Hercules could have borne the burdens of undivided sovereignty in an age of turbulence, treason, revolts, and anarchies. It was probably much easier for Tiberius or Trajan to rule the whole world than for one of the later emperors to rule a province. Alfred had a harder task than Charlemagne, and Queen Elizabeth than Queen Victoria.