but in time it became as corrupt itself, and for the corruption of a despotism there is no cure. A succession of able rulers put off the end for a time, but it had to come. And when it came there came with it more vigorous races out of whom was to be formed by degrees, not without help of the old order which they swept away, a new civilisation. Commodus, the unworthy son and successor of the good Aurelius, reigned but for a short time. He was assassinated in his thirty-second year. With his death began, it may be said, the rule of the sword. His successor, indeed, Pertinax by name, was chosen by the Senate, and well deserved his election, but he reigned for something less than ninety days, and the Prætorians, the soldiers of the capital, murdered him and sold the throne openly to the highest bidder. To this arrogance the legions in the provinces refused to submit. The principal armies put up candidates of their own. We need not follow the succession of these short-lived rulers. It will suffice to say that in the hundred and five years which intervened between the death of Aurelius and the accession of Diocletian (180-285) there were no less than twenty Emperors, not to mention innumerable Pretenders--it was said that at one time thirty[45] claimed the throne. For a time the spectacle of the Roman armies engaged in almost incessant struggles with each other does not seem to have produced the effect which might have been expected on the tribes outside the frontiers of the Empire. No movement of any importance among the barbarians is recorded during the fifty years which followed the murder of Pertinax by the Prætorians. In 209, indeed, the Britons of the north attacked the Roman province, and were punished, without any lasting effect, by Septimius Severus. But the event was of no particular importance, for the North Britons were not powerful enough, even if they had succeeded, to seriously affect the course of events. Causes with which we are not exactly acquainted kept the far more formidable tribes of Germany inactive. We hear of a combination among them in the reign of Aurelius which might well have become dangerous, if, to use the language of Gibbon, it included all the nations from the mouth of the Rhine to the mouth of the Danube. But it came to nothing. The tribes which first took the field were defeated. Discouragement and dissension kept the others inactive. Dissension, indeed, was the most potent influence which worked in favour of the Romans. In his remarkable treatise on Germany and its tribes Tacitus gives a description of the people which emphasises their superiority in many important respects to the degenerate sons of Rome. But he speaks with satisfaction of the internal strife which prevented them from becoming formidable, mentioning one great conflict in which one tribe had been wholly destroyed by its neighbours, and adds, "While the destinies of Empire hurry us on, fortune can give us no greater boon than discord