The Mongol Invasion

If your saga follows the course of history, by the end of the reign of al-Nasir the eastern Muslim world has already been attacked by the Mongol hordes of Genghis Khan (r. 1206-1227), who have occupied the region east of the Jaxartes River. By Genghis Khan's death they have occupied territory as far west as eastern Persia. Subsequently they take western Persia, Georgia, Armenia, northern Iraq, and Asia Minor. In 1258 they take Baghdad, where they roll the caliph up in a carpet and trample him to death, following a Mongol custom that forbids the shedding of royal blood onto the ground. They are only turned back in 1260, when their advance is checked in Syria by a Mamluk army from Egypt.