 The Franks of Acre did their best to maintain a position of cautious neutrality between the Mongols and the Mamluks . Despite their long history of enmity with the Mamluks , the Franks acknowledged that the Mongols were a greater threat , and after careful debate , chose to enter into a passive truce with their previous adversaries . The Franks allowed the Mamluk forces to move northward through Christian territory to engage the Mongols , in exchange for an agreement that the Franks could purchase any captured Mongol horses at a low price . The truce allowed the Mamluks to camp and re @-@ supply near Acre , and engage the Mongols at Ain Jalut on September 3 , 1260 . The Mongol forces were already depleted due to their main force withdrawing , so with the passive assistance of the Franks , the Mamluks were able to achieve a decisive and historic victory over the Mongols . The remainder of the Mongol army retreated to Cilician Armenia , where they were received and re @-@ equipped by Hethum I. Ain Jalut marked a major turning point in the history of the Mongols , as it was the first major battle that they had lost , and set the western border for what had seemed an unstoppable expansion of the Mongol Empire . 
