The political complications with which Henry was surrounded were still further confused by a new question which now arose, and which was to threaten the peace of Europe for eighteen years. On the death of the English Pope, Hadrian IV., on the 1st of September 1159, two rivals, Alexander III. and Victor IV., disputed the see of Rome, and the strife between the Empire and the Papacy, now nearly one hundred years old, broke out afresh on a far greater scale than in the time of Gregory. Frederick Barbarossa asserted the imperial right of judging between the rivals, and declared Victor pope, supported by the princes of the Empire and by the kings of Hungary, Bohemia, and Denmark. Alexander claimed the aid of the French king--the traditional defender of the Church and protector of the Popes; and after the strife had raged for nearly three years, he fled in 1162 to France. In the great schism Henry joined the side of Louis in support of Alexander and of the orthodox cause; the two kings met at Chouzy, near Blois, to do honour to the Pope; they walked on either side of his horse and held his reins. The meeting marked a great triumph for Alexander; the union of the Teutonic nations against the policy of Rome was to be delayed for three centuries and a half. It marked, too, the highest point of Henry's success. He had checked the Emperor's schemes; he had won the gratitude of both Louis and the Pope; he had defeated the plots of the House of Blois, and shown how easily any alliance between France and Champagne might be broken to pieces by his military power and his astute diplomacy. He had rounded off his dominions; he had conquered the county of Cahors; he had recovered the Vexin and the border castles of Fréteval and Amboise; the fiefs of William of Boulogne had passed into his hands on William's death; he was master of Nantes and Dol, and lord of Britanny; he had been appointed Protector of Flanders.