 European attitudes began to change in the mid @-@ 1260s , from perceiving the Mongols as enemies to be feared , to potential allies against the Muslims . The Mongols sought to capitalize on this , promising a re @-@ conquered Jerusalem to the Europeans in return for cooperation . Attempts to cement an alliance continued through negotiations with many leaders of the Mongol Ilkhanate in Iran , from its founder Hulagu through his descendants Abaqa , Arghun , Ghazan , and Öljaitü , but without success . The Mongols invaded Syria several times between 1281 and 1312 , sometimes in attempts at joint operations with the Franks , but the considerable logistical difficulties involved meant that forces would arrive months apart , never able to coordinate activities in any effective way . The Mongol Empire eventually dissolved into civil war , and the Egyptian Mamluks successfully recaptured all of Palestine and Syria from the Crusaders . After the Fall of Acre in 1291 , the remaining Crusaders retreated to the island of Cyprus . They made a final attempt to establish a bridgehead at the small island of Ruad off the coast of Tortosa , again in an attempt to coordinate military action with the Mongols , but the plan failed , and the Muslims responded by besieging the island . With the Fall of Ruad in 1302 or 1303 , the Crusaders lost their last foothold in the Holy Land . 
