When the loss of Damietta and the evacuation of Egypt was known at Rome, Pope Honorius III. reproached the emperor, Frederic II. with being the cause of the signal failure of the christian arms in the East, and threatened him with excommunication if he did not immediately fulfil his vow, by leading his armies against the Infidel. This insolence roused the indignation of the prince, and excited him to hostility. He proceeded to claim the kingdom of the two Sicilies, in right of his mother, Constance, and marching thither, drove out the partisans of the Holy See, established bishops of his own choosing in the vacant benefices, and even threatened to plunder Rome. Honorius discovering that he had involved himself in strife with a powerful enemy, wrote a conciliatory letter to the emperor, saying, "I exhort you, my dear son, to recall to your recollection, that you are the protector of the Roman Church; do not forget what you owe to that good mother, and take pity on her daughter, the church of the East, which extends towards you her arms, like an unfortunate, who has no longer any hope but in you." Frederic, too much occupied in his plans for adding Italy to the German Empire, to undertake a distant expedition that afforded so little prospect of an increase of patrimony or glory, was, notwithstanding, willing to avail himself of the popular enthusiasm. He professed his intention to obey the mandate of the holy father, and prepared for the pious work, by causing his son Henry to be crowned King of the Romans, and by adding the imperial to the kingly diadem upon his own head, 1220. It is even probable that the subjugation of Italy, and the assertion of the rights of the temporal against the spiritual power, might have prevented Frederic from ever attempting anything for Palestine, had not the sagacious pontiff found an irresistible ally in the beautiful Violante, Queen of Jerusalem. Wearied of endeavoring to convert his marital rights to the sovereignty of Jerusalem, into actual and firm dominion, Jean de Brienne listened to the suggestions of the Roman legate, that his claims to the nominal crown might be transferred with the hand of his daughter to some powerful prince of Europe.