After a two-week siege, Hulagu Khan's Mongol army breached Baghdad's walls and unleashed days of slaughter and destruction. The Abbasid Caliph al-Mustasim was captured and executed, the House of Wisdom's libraries were destroyed, and the Tigris River reportedly ran black with ink from discarded books and red with blood.
Baghdad in 1258 was the intellectual capital of the Islamic world, home to the House of Wisdom, a legendary center of translation and scholarship where Greek, Persian, and Indian knowledge had been preserved and expanded for centuries. When Hulagu Khan's Mongol army arrived demanding submission, Caliph al-Mustasim underestimated the threat, believing divine protection and the city's reputation would suffice.
He was wrong. Mongol siege engines breached the walls, and what followed was one of history's most catastrophic cultural losses. Estimates of the dead range from 90,000 to nearly a million. Libraries containing irreplaceable manuscripts were tossed into the Tigris in such quantities that witnesses claimed the river turned black with ink, then red with the blood of scholars.
Al-Mustasim was executed, reportedly rolled in a carpet and trampled by horses to avoid spilling royal blood on the ground, per Mongol custom regarding rulers. The fall of Baghdad marked the definitive end of the Abbasid Caliphate's political power and is often cited as a turning point after which the Islamic Golden Age's momentum never fully recovered.