Baghdad’s defenses are ruined within three days, while Mongol engineers are destroying the irrigation dikes to flood the city and drown the defenders.

The caliph and three hundred officials hurry to present their surrender and, ten days later, are all executed, Musta'sim and all but one of his sons by being rolled in carpets and trampled to death by horses.

The sole surviving son is sent to Mongolia.

This leaves Islam without a caliph for the first time in its history, a blow from which Islamic civilization will never fully recover.

After securing the city’s defeat on February 10, 1258, the Mongols loot the city and burn it to the ground.

The survivors are then assembled on the plain outside the city, where they are shot and hacked to death, their corpses piled in heaps.

Over a period of days, between ninety thousand and one million men, women and children are slain in a mass slaughter of all the inhabitants except Christians, themselves spared by the intervention of Hulagu’s Nestorian Christian wife Dokuz Khatun.

Baghdad, its dikes destroyed and its irrigation canals filled in by the Mongols and no citizens left to restore it, is to remain a depopulated, ruined city for several centuries and will only gradually recover some of its former glory.