The Mongols and the fall of Baghdad

Hulagu, grandson of Genghis Khan, comes against Baghdad with an enormous army, and after a short siege the city surrenders. The capital is plundered and burned for days; the last Abbasid caliph is executed — by tradition, rolled in a carpet, so that royal blood should not be spilled on the ground. The libraries perish, and the irrigation channels that had been tended for centuries; Mesopotamia never returns to its former plenty. With Baghdad ends an epoch of five hundred years: the centre of the Muslim world shifts to Cairo, and the Babylonian Jewish academies, long fading, finally lose their primacy.