the proposal. Eventually, all eastern European rulers still not under Mongol domination had now joined Innocent’s alliance, however short-lived. In September 1243, he issued the bull Qui iustis causis, authorizing further Northern Crusades. Innocent IV was determined in his goal of the destruction of Frederick II. The attempts undertaken by Louis IX to bring about peace were of no avail. In 1249 the pope ordered a crusade to be preached against Frederick II, and after the emperor's death in December 1250, he continued the struggle against Conrad IV of Germany and his half-brother Manfred of Sicily with unrelenting severity. The crown of Sicily had devolved upon the Holy See after the deposition of Frederick II, and Innocent first offered it to Richard of Cornwall and Edmund Crouchback, brother and son of Henry III of England. After the death of Conrad IV in May 1254, the pope finally recognized the hereditary claims of Conrad's two-year-old son Conradin. Manfred also submitted, but soon revolted and defeated the papal troops at the Battle of Foggia on 2 December 1254. Innocent IV died a few days later. Negotiations with the Mongols In 1245, Innocent IV supplemented efforts in the Holy Land and Baltics by sending two embassies to Mongolia to the court of the Great Khan, beginning the attempts at a Franco-Mongol alliance. The first was led by the Franciscan John of Plano Carpini, traveling across Russia and Central Asia to Karakorum. In August 1246, he witnessed a Kuriltayi that elevated Güyük Khan to power. Güyük, after receiving the pope’s request for him to accept Christianity, demanded that the pope acknowledge his suzerainty and to come to pay him homage. Upon his return at the end of 1247, John reported to Rome that the Mongols were only out for conquest. His second embassy was the Dominican Ascelin of Lombardy who travelled to meet the Mongol general Baiju Noyan at Tabriz in May 1247. Baiju and Ascelin discussed an alliance against the Ayyubids. He planned to attack Baghdad, and it would suit him to have the Syrians distracted by a crusade of the Franks. He sent his envoys, Aïbeg and Serkis, with Ascelin to Rome causing the hopes of the West rise again. In November 1248, they returned to Baiju with no further action on the proposed alliance. Preparations In 1244, the peace of the previous decade was quickly swept away, negating prospects that appeared