In 1244, the Khwarezmians, recently displaced by the advance of the Mongols, took Jerusalem on their way to ally with the Egyptian Mamluks. This returned Jerusalem to Muslim control, but the fall of Jerusalem was no longer a crucial event to European Christians, who had seen the city pass from Christian to Muslim control numerous times in the past two centuries. This time, despite calls from the Pope, there was no popular enthusiasm for a new crusade. There were also many conflicts within Europe that kept its leaders from embarking on the Crusade.
Pope Innocent IV and Frederick II, Holy Roman Emperor continued the papal-imperial struggle. Frederick had captured and imprisoned clerics on their way to the First Council of Lyon, and in 1245 he was formally deposed by Innocent IV. Pope Gregory IX had also earlier offered King Louis' brother, count Robert of Artois, the German throne, but Louis had refused. Thus, the Holy Roman Emperor was in no position to crusade. Béla IV of Hungary was rebuilding his kingdom from the ashes after the devastating Mongol invasion of 1241. Henry III of England was still struggling with Simon de Montfort and other problems in England. Henry and Louis were not on the best of terms, being engaged in the Capetian-Plantagenet struggle, and while Louis was away on crusade the English king signed a truce promising not to attack French lands. Louis IX had also invited King Haakon IV of Norway to crusade, sending the English chronicler Matthew Paris as an ambassador, but again was unsuccessful. The only king interested in beginning another crusade therefore was Louis IX, who declared his intent to go east in 1245. A much smaller force of Englishmen, led by William Longespée, also took the cross.