Having suppressed a rising at Mainz Frederick set out in the autumn of 1163 for Italy, which country was now distracted by a papal schism. This incident was bound to affect German politics. After the death of Adrian IV. in 1159 the imperial party put forward an anti-pope, Victor IV., against Alexander III., who had been canonically elected. The emperor made stupendous efforts to secure for Victor and then for his successor, Paschal III., recognition by the sovereigns of Europe, but in vain; and almost the only support which the anti-pope received came from the German clergy. In May 1165 Frederick held a diet at Würzburg, where the princes lay and clerical swore to be faithful to Paschal and never to recognize Alexander. But Alexander soon found partisans among the German clergy, hitherto the most loyal of the emperor's friends; and Frederick retaliated by driving the offending prelates from their sees, a proceeding which tended to disturb the peace of the land. Then in August 1167, in the midst of the struggle in Italy, came the pestilence which destroyed the imperial army in Rome, and drove the emperor as a fugitive across the Alps. After this humiliation Frederick remained for six years in Germany. He was fully occupied in restoring order in Saxony, in the diocese of Salzburg and elsewhere; in adding to his hereditary lands; in negotiating for a better understanding with France and England; and in reminding the vassal states, Hungary, Poland and Bohemia, of their duties towards the Empire. The success with which he carried out this work shows clearly that, in Germany at least, the disaster at Rome had not seriously affected his prestige. Again in Italy in 1174 the contest with the Papacy was abruptly ended by Frederick's overwhelming defeat at Legnano in May 1176, and by the treaty of Venice made about a year later with Alexander III. Frederick and Henry the Lion.