His successor was Gregory IX, a relative of Innocent III who had made him a Cardinal and employed him on important embassies. He has been described as a man "of strong passions and an iron strength of will." He is said to have been more than eighty years of age at his accession; but he was vigorous and alert in mind and body, a man of blameless life and ardent faith, eloquent and learned, especially in law. Hitherto he had been friendly to Frederick. But he held views even more advanced than those of Innocent regarding the power of the Papacy. Hence, while to Honorius the Crusade was the end towards which his whole policy was directed, Gregory only desired to use the crusading vow taken by temporal rulers as a weapon for the assertion of the papal power against them. It was Gregory who as Cardinal Ugolino had placed the cross in Frederick's hand at his imperial coronation. As Pope he now demanded the immediate fulfilment of Frederick's promise; and despite his reluctance to go and the outbreak of an epidemic in his army, Frederick embarked at Brindisi on September 18th, 1227. But three days later under the plea of sickness he turned back. Gregory never hesitated. On September 29th in the cathedral of Anagni in fulfilment of the terms agreed to by Frederick himself, he excommunicated the Emperor with the accompaniment of every kind of impressive ceremonial. There seems little doubt that the cause of Gregory's determination to exact from Frederick the utmost penalty for his failure to carry out the agreement lay in Frederick's Italian policy. Frederick had postponed the crusade in order to build up a power in Sicily, which he was now trying to extend to North Italy by crushing the Lombard League. This was a fatal bar to the policy of a papal state in Central Italy, inaugurated by Innocent III. No less imminent was the danger from the success of Frederick in baffling the papal schemes for the separation of the Sicilian and German crowns. It was becoming apparent that only by the extinction of the Hohenstaufen line could the papal policy be carried out. [Sidenote: Frederick's crusade.]