As regards the provinces the change from senatorial to imperial government at Rome was a great gain, inasmuch as it substituted an orderly and responsible administration for irregular and irresponsible extortion. For a long time, too, it was no part of the imperial policy to interfere with local customs and privileges. But, in the absence of a representative system, the centralizing tendency inseparable from the position of such a government proved to be irresistible. And the strength of this centralizing tendency was further enhanced by the military character of the government which was necessitated by perpetual frontier warfare against the barbarians. As year after year went by, the provincial towns and cities were governed less and less by their local magistrates, more and more by prefects responsible to the emperor only. There were other co-operating causes, economical and social, for the decline of the empire; but this change alone, which was consummated by the time of Diocletian, was quite enough to burn out the candle of Roman strength at both ends. With the decrease in the power of the local governments came an increase in the burdens of taxation and conscription that were laid upon them.[14] And as "the dislocation of commerce and industry caused by the barbarian inroads, and the increasing demands of the central administration for the payment of its countless officials and the maintenance of its troops, all went together," the load at last became greater "than human nature could endure." By the time of the great invasions of the fifth century, local political life had gone far towards extinction throughout Roman Europe, and the tribal organization of the Teutons prevailed in the struggle simply because it had come to be politically stronger than any organization that was left to oppose it.