After conquering Baghdad, the Mongol Hulagu, grandson of Genghis Khan, massacred hundreds of thousands of its citizens, and threw so many books into the Tigris that it was said a horse could cross it. The Caliph was wrapped in a carpet and beaten to death by horses, in accordance with the Mongol belief that the soil could not be offended by royal blood. The level of destruction in the city was such that, after the sack of Baghdad, the Mongols were forced to move their military camp elsewhere.
