 Most historians describe the contacts between the Mongol Empire and the Western Europeans as a series of attempts , missed opportunities , and failed negotiations . Christopher Atwood , in the 2004 Encyclopedia of Mongolia and the Mongol Empire , summed up the relations between Western Europe and the Mongols : " Despite numerous envoys and the obvious logic of an alliance against mutual enemies , the papacy and the Crusaders never achieved the often @-@ proposed alliance against Islam . " 
