Evidently the original error of the Romans was the undue extension of their power. This was recognised by no less a statesman than Augustus, the founder of the Empire; but even in his time it was too late to sound a retreat; he could only register a protest against further annexations. Embracing the whole of the Mediterranean littoral and a large part of the territories to the south, east, and north, the Empire was encumbered with three land frontiers of enormous length. Two of these, the European and the Asiatic, were perpetual sources of anxiety, and called for separate military establishments. That neither might be neglected in the interest of the other it was reasonable to put the imperial power in commission between two colleagues. Diocletian (284-305 A.D.) was the first to adopt this plan; from his time projects of partition were in the air and would have been more regularly carried out, had not experience shown that partitions led naturally to civil wars between rival Emperors. In 395, on the death of the great Theodosius, the hazardous expedient was given a last trial. His youthful sons, Arcadius and Honorius, were allowed to divide the Empire; but the line of partition was drawn with more regard to racial jealousies than military considerations. It extended from the middle Danube (near Belgrade) to a point near Durazzo on the Adriatic coast, and thence to the Gulf of Sidra. East of this line lay the sphere of Greek civilisation, the provinces which looked to Alexandria and Antioch and Constantinople as their natural capitals. West of it the prevailing language was Latin, and the higher classes of society modelled themselves upon the Italian aristocracy. Founded upon a principle which appeals to our modern respect for nationality, this partition only gave a legal form to a schism which had been long in preparation. But in one respect it was disastrous. The defence of the Danube frontier was divided between the two governments; and that of the East, rating the impoverished Balkan peninsula as of secondary importance, and envisaging the problem from a wholly selfish point of view, left unguarded the great highways leading from the Danube into Italy. Stilicho, the great general who administered the West in the name of Honorius, ventured to meet this danger by intervening in the peninsula, and even in the political intrigues of Constantinople. He only succeeded in winning a precarious alliance with the Visigoths and the permanent ill-will of the Eastern Empire. He was left to deal single-handed with the first invaders of Italy; and the estrangement of the two imperial courts persisted after his untimely fall. The Western Empire, betrayed by the one possible ally, collapsed under the strain of simultaneous attacks along the whole line of the European frontier.