The work of the eighteen Popes who occupied the throne between the death of Gregory VII. and the election of Innocent might not ineptly be described in a line: they sought, and failed, to wield the heavy weapons of Hildebrand. In virtue of the falsified letters, canons, charters, and chronicles which were now accepted throughout Europe, they proclaimed that they had the disposal of earthly kingdoms no less than of seats in heaven, and they thus brought on themselves a century of strife in which only the stronger men could find much time for strictly Pontifical duties. They were men of sober life and, generally, high character, yet the very nature of their ideal involved such struggles that the Papacy had to await a fortunate conjunction of circumstances before the ideal could be realized. The conflict with Henry IV. continued until, his two sons having been persuaded to rebel against him and his second wife encouraged to besmirch his reputation, before the assembled prelates of Christendom, with charges as foul as they were feeble in evidence, he, in 1097, quitted Italy for ever. Then Urban II., who was responsible for this gross travesty of spiritual justice, cleared Rome by means of Norman swords and rallied Christendom about him by a declaration of the First Crusade. But so tainted a legacy of peace could not last. Henry V. proved more exacting than his father, and another prolonged struggle absorbed the energy of the Popes until the fifty years' war over investiture was settled by a compromise at Worms in 1122.[237] Bernard of Clairvaux, rather than the successive Popes, was the spiritual master of Europe in the comparative peace after Worms. During nearly the whole of the second half of the twelfth century the Papacy was distracted by the incessant revolts of the Romans. The streets, even the churches, of Rome were stained with blood, year after year, and the Popes repeatedly fled. The rise of Frederic Barbarossa complicated the struggle, and the Popes had little opportunity to exercise the powers they had won, without thinking of any extension of their claims. At last, in 1198, the Papacy once more fell to a man of commanding personality and was lifted to the zenith of its power.