Siege of Baghdad
Mongol sack of Baghdad in 1258 ended Abbasid rule.
In early 1258, the Mongol prince Hulegu led a massive army against Baghdad, the historic seat of the Abbasid Caliphate. The attack followed a series of provocations by the city’s ruler, Caliph al-Musta'sim. Within weeks, Baghdad was captured and plundered; the caliph and hundreds of thousands of his people were killed. While the city’s fall is often cited as the end of the Islamic Golden Age, its actual long-term effects remain unclear.
Hulegu, a grandson of Genghis Khan, was sent west to Persia after his brother Möngke Khan became the Mongol ruler in 1251. His army, over 138,000 strong, took years to reach the region but quickly subdued the Nizari Ismaili Assassins in 1256. The Mongols had expected al-Musta'sim to send reinforcements for their campaign. When he failed to do so and showed arrogance in negotiations, Hulegu decided to overthrow him by late 1257. Invading Mesopotamia from multiple directions, the Mongol army neared Baghdad and routed a sortie on 17 January 1258 by flooding the enemy camp. They then besieged the city, which had only about 30,000 defenders.
The assault began in late January. Mongol siege engines breached Baghdad’s walls within days, and Hulegu’s elite troops controlled the eastern wall by 4 February. Desperate, al-Musta'sim tried to negotiate, but Hulegu sought total victory, even killing soldiers who tried to surrender. The caliph finally gave up the city on 10 February, and the Mongols started looting three days later. The exact death toll is unknown, as epidemics likely raised the number; Hulegu later estimated it at around 200,000. After calling a halt to the pillaging on 20 February, Hulegu executed the caliph. Despite later Muslim historians’ exaggerations, Baghdad actually prospered under Hulegu’s Ilkhanate, though it declined relative to the new capital, Tabriz.
Baghdad was founded in 762 by Caliph al-Mansur of the Abbasid dynasty, which had just overthrown the Umayyads. Al-Mansur wanted a new capital safe from threats and close to the dynasty’s Persian power base. Thanks to its control of trade routes and taxes, Baghdad grew incredibly wealthy and became a world city, the heart of the Islamic Golden Age. Poets, writers, scientists, philosophers, musicians, and scholars of all kinds thrived there. With institutions like the House of Wisdom and astronomical observatories, using paper and gathering ancient knowledge from
- Date
- Early 1258
- Location
- Baghdad, Abbasid Caliphate
- Commanders
- Hulegu (Mongol Empire); al-Musta'sim (Abbasid Caliphate)
- Outcome
- Mongol victory; sack of Baghdad
- Estimated deaths
- Around 200,000 (Hulegu's estimate); unknown total due to epidemics
- Forces involved
- Mongol army over 138,000 men; Baghdad defenders around 30,000 troops
Lore & Background
Hulegu, a grandson of Genghis Khan, was dispatched westwards by his brother Möngke Khan after 1251 to secure Persia. His massive army of over 138,000 men took years to reach the region but quickly attacked and overpowered the Nizari Ismaili Assassins in 1256. The Mongols had expected al-Musta'sim to provide reinforcements for their army—the Caliph's failure to do so, combined with his arrogance in negotiations, convinced Hulegu to overthrow him in late 1257. Invading Mesopotamia from all sides, the Mongol army soon approached Baghdad, routing a sortie on 17 January 1258 by flooding their opponents' camp. They then invested Baghdad, which was left with around 30,000 troops.
The assault began at the end of January. Mongol siege engines breached Baghdad's fortifications within a couple of days, and Hulegu's highly-trained troops controlled the eastern wall by 4 February. The increasingly desperate al-Musta'sim frantically tried to negotiate, but Hulegu was intent on total victory, even killing soldiers who attempted to surrender. The Caliph eventually surrendered the city on 10 February, and the Mongols began looting three days later. The total number of people who died is unknown, as it was likely increased by subsequent epidemics; Hulegu later estimated the total at around 200,000. After calling an amnesty for the pillaging on 20 February, Hulegu executed the caliph.
Reader's Guide
The Siege of Baghdad is significant as a pivotal event in the expansion of the Mongol Empire under Hulegu, marking the end of the Abbasid Caliphate's political power. The city, founded in 762 by al-Mansur, had been the epicentre of the Islamic Golden Age, a world city of immense wealth and learning. Its fall has traditionally been seen as ending that Golden Age, though the article notes that its actual ramifications are uncertain. In contrast to later Muslim historians' exaggerations, Baghdad prospered under Hulegu's Ilkhanate, although it declined relative to the new capital, Tabriz. The siege demonstrates Mongol military efficiency—using siege engines, flooding tactics, and overwhelming force—and the consequences of diplomatic miscalculation by al-Musta'sim, who refused to submit or provide troops. The event also highlights the role of internal divisions, such as sectarian violence between Sunnis and Shi'a in Baghdad, and accusations of betrayal against the vizier Muhammad ibn al-Alqami. The uncertainty over the death toll and the long-term effects underscores the complexity of historical interpretation.
Did You Know?
- Hulegu's army included a thousand-strong corps of military engineers led by Guo Kan.
- The caliph al-Musta'sim was executed after an amnesty for pillaging was called on 20 February 1258.
- Baghdad was founded in 762 by al-Mansur, the second caliph of the Abbasid dynasty.
- The Mongols had expected al-Musta'sim to provide reinforcements for their campaign against the Assassins.
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