The fall of Baghdad to the Mongols

Hulagu's Mongol army entered Baghdad, seat of the Abbasid caliphate, after a strangling siege. They pillaged it for forty days and killed hundreds of thousands, and the caliph al-Mustaʿsim was slain — closing the page on a caliphate that had lasted five centuries.

Hulagu, grandson of Genghis Khan, advanced with vast armies toward Baghdad in late 655 AH and laid siege to it. The caliph al-Mustaʿsim bi'llah was unable to repel him after the army had been neglected, unity had fractured, and the inner circle had betrayed him.

On the fourth of Safar 656 AH (February 1258) the Mongols entered the city, and there occurred killing and plunder that make the body shudder; the dead were estimated in the hundreds of thousands, and the books of Baghdad's libraries were cast into the Tigris until, it was said, its water ran black with ink.

The caliph al-Mustaʿsim was killed days later, and the Abbasid caliphate in Baghdad fell after five centuries. Historians counted this catastrophe among the greatest calamities of Islam — until the Muslims returned the blow at ʿAyn Jalut two years later.