The succeeding period of European history, in Gaul, Spain, Africa, and Italy, is the mingling or attempted mingling of the old populations of the Empire with the Barbarian conquerors. The process had, indeed, as I have intimated, begun before the fall of the Empire. For several generations Barbarians had not only been received as colonists and taken as soldiers, but even whole tribes had been admitted within the Roman boundaries. Imperial statesmen had realized that the Empire could only be upheld by an infusion of Barbarian virility, and they had favoured the process. But assimilation had not taken place, and now that the Empire had passed into the hands of the Barbarians there were two social strata,--the rude martial conquerors on top, and the civilized, feeble, subject race, ten times as numerous, underneath. It was obvious to the wiser Barbarian chiefs, trained as they were in Roman ways, that if they were to get stable dominion and civilized government, they must adopt the complicated Imperial machinery. They saw that unless the Barbarians learned Roman civilization, they would need hundreds of years to create any such civilization of their own. This was especially true in Italy. Odoacer, the general who deposed Romulus Augustulus, well knew that a state which had its military service all Barbarian and its civil service all Roman could not stand firm. Barbarian sovereignty needed support, especially legal support, in the eyes of the subject population. Such legitimacy could only come from the Empire. Odoacer and other intelligent Barbarians turned instinctively to Constantinople for recognition. They did not think that they had overturned or suppressed the Empire. Nobody thought that there were two Empires, one Eastern and one Western, one enduring and one destroyed in 476. To the Roman world the Empire had always been single, had always been a unit. The division into eastern and western parts had been made for convenience of administration; the Empire itself had never been divided. Even after the western countries of Europe had been overrun by the Barbarians, the Emperor at Constantinople remained the supreme and sole source of authority and law. The very Barbarians could not free themselves from this theory, however little heed they paid to it in practice. Odoacer acknowledged the sovereignty of the Empire without question. He merely wished to control the civil and military administration in Italy.