Hülegü’s Mongols Sack Baghdad and End the Abbasid Caliphate

In January 1258, a vast Mongol army commanded by Hulegu, a grandson of Genghis Khan, converged on Baghdad. Established as the capital of the Abbasid Caliphate in 762 by the caliph al-Mansur, the metropolis had flourished as a prominent center of commerce and scholarship, home to renowned institutions such as the House of Wisdom. Yet centuries of political fragmentation had significantly reduced caliphal power. By the time al-Musta'sim assumed the throne, the dynasty held direct authority primarily over Iraq, leaving the capital vulnerable to external threats.

The confrontation followed years of mounting tension across western Asia. Dispatched by his brother Mongke Khan to secure Persia and subdue recalcitrant states, Hulegu oversaw a very large force drawn from across the empire and its vassals, although its exact size is uncertain. After dismantling the Nizari Ismaili fortresses in late 1256, Hulegu sought troops and formal submission from al-Musta'sim. The caliph, misjudging his strategic position and refusing to dispatch the required contingents, met Mongol demands with defiance and inadequate concessions, prompting Hulegu to order a coordinated invasion of Mesopotamia.