Siege of Baghdad (1258): Mongols End the Abbasid Caliphate

The siege of Baghdad in 1258 was the Mongol attack on the capital of the Abbasid caliphate, led by Hulagu, grandson of Genghis Khan. After a siege of under two weeks, Caliph al-Musta’sim surrendered on 10 February 1258; the city was sacked, a huge number of its people were killed and the caliph himself was executed. The fall of Baghdad ended five centuries of Abbasid rule from the city and is remembered as one of the great catastrophes of Islamic history.

Background: Baghdad and the Mongols

Baghdad had been founded by the Abbasid caliph al-Mansur in 762 (see Founding of Baghdad). For centuries it was one of the largest and most cultured cities on earth. By the 13th century, however, the Abbasid caliphate had long lost most of its political power. The caliphs had been dominated in turn by Buyid and Seljuk rulers, and only in the late 12th century had they recovered real control over central Iraq.

The Mongols, meanwhile, had built the largest land empire in history. Genghis Khan’s armies destroyed the Khwarazmian Empire in Central Asia and Iran from 1219, and Mongol forces under the general Baiju defeated the Seljuks of Anatolia at Köse Dağ in 1243.

In 1251 Möngke became Great Khan. He sent one brother, Kublai, against Song China and the other, Hulagu, to the west. Hulagu’s orders were to subdue the Nizari Ismailis of Iran, often called the Assassins, and to demand the submission of the caliph.

Hulagu’s campaign

Hulagu left Mongolia in 1253 and advanced slowly with a huge army, often estimated at 100,000 to 150,000 men once allied contingents are included. In 1256 he took the Ismaili mountain fortresses, and the Ismaili leader Rukn al-Din Khurshah surrendered. Among the scholars who passed into Hulagu’s service from the Ismaili castles was the astronomer and philosopher Nasir al-Din al-Tusi.

Hulagu then sent letters to Caliph al-Musta’sim (ruled 1242–1258), demanding that he come in person or send his chief ministers to submit. The caliph refused, replying that the whole Muslim world would rise to defend him. In fact he had a small army and few allies.

Divided counsels in Baghdad

The caliph’s court was split. His vizier, Ibn al-Alqami, a Shiite, is said to have urged negotiation and is accused in many Sunni sources of secretly helping the Mongols, a charge historians treat with caution. The chief secretary and army commander, Mujahid al-Din Aybak, known as the dawatdar, favoured resistance.

Little was done to strengthen the defences or to raise a large army in time. Many historians see al-Musta’sim as a ruler who overrated both his religious prestige and the willingness of other Muslim princes to come to his aid.

What happened: the siege

In late 1257 the Mongols converged on Baghdad from several directions. Hulagu came from the east, while Baiju crossed the Tigris to approach from the west.

In mid-January 1258 the dawatdar led the caliph’s field army out against Baiju near Anbar on the Euphrates. After an initial clash, the Mongols broke the dykes behind the Abbasid camp, flooding it. Thousands of soldiers drowned or were killed, and only a few, including the dawatdar, escaped back into the city.

The assault on the walls

From about 29 January 1258 Baghdad was fully encircled. The Mongols built a palisade and ditch around the city and brought up catapults and siege engines, operated in part by Chinese engineers. They also placed boats and pontoons across the Tigris to stop anyone escaping by river.

The heaviest bombardment fell on the eastern walls, around the Persian (Ajami) Tower. By 4 or 5 February the Mongols held much of the eastern wall. The caliph sent envoys and gifts, but Hulagu refused to bargain. The dawatdar was killed when he tried to leave the city, and members of the court began to surrender.

On 10 February 1258 al-Musta’sim came out with his sons and officials and surrendered to Hulagu.

The sack of Baghdad

After the soldiers who had laid down their arms were killed, the Mongols entered the city, and the sack began around 13 February. For about a week the city was looted and burned and its inhabitants massacred. Mosques, palaces, libraries and the tombs of earlier caliphs were damaged or destroyed.

Not everyone was killed. The Christian population, who had taken refuge in a church, were spared, a decision often linked to Hulagu’s influential wife Doquz Khatun, a Nestorian Christian. Some merchants and notables bought their safety, and a number of scholars and craftsmen were taken into Mongol service.

The death of the caliph

Al-Musta’sim was forced to reveal the treasures of the palace. Around 20 February he was put to death together with most of his family. Several sources say he was rolled in a carpet and trampled or beaten, a method reflecting a Mongol taboo against spilling royal blood on the ground. The exact details vary between accounts.

Why Baghdad fell so quickly

Several factors explain the speed of the collapse. The first was the sheer imbalance of force. The caliph’s army was small and poorly prepared, and its best field force had already been destroyed near Anbar before the siege began. Baghdad’s walls had not been designed to withstand the large siege engines and organised engineering that the Mongols had learned to use in China and Central Asia.

The second was isolation. No Muslim ruler sent a significant army to help. The Ayyubid princes of Syria were divided and frightened, the rulers of Mosul and Anatolia had already submitted to the Mongols, and some even sent contingents to Hulagu’s army. The Mamluks of Egypt were far away and absorbed in their own power struggles.

The third was leadership. Al-Musta’sim appears to have believed until very late that his office would protect him, as it had protected earlier caliphs against Buyid and Seljuk overlords. The Mongols, however, recognised no such sacred status. Their practice was simple: cities that submitted promptly could be spared, while those that resisted could expect harsh punishment, and Baghdad had defied repeated demands to surrender.

Key people

• Hulagu (c. 1217–1265): grandson of Genghis Khan and founder of the Mongol state in Iran known as the Ilkhanate.
• al-Musta’sim (1213–1258): the 37th and last Abbasid caliph to rule in Baghdad.
• Ibn al-Alqami: the caliph’s vizier, kept in office briefly by the Mongols; he died in 1258.
• Baiju: Mongol general who commanded the western wing and destroyed the caliph’s army near Anbar.
• Nasir al-Din al-Tusi (1201–1274): scholar who accompanied Hulagu and later built the observatory at Maragheh.

By the numbers

Consequences

The fall of Baghdad ended the Abbasid caliphate as a political institution in Iraq. For Sunni Muslims, the loss of the caliph, the symbolic head of the community, was a profound shock. Poets wrote laments for the city, and the event coloured Muslim views of the Mongols for generations.

Iraq became a province of Hulagu’s new state, the Ilkhanate, ruled from Azerbaijan. Baghdad recovered partly and remained an important provincial city, but it never regained its earlier pre-eminence. The damage to irrigation and the countryside of central Iraq was also long-lasting.

Hulagu moved on to Syria, taking Aleppo in January 1260 and receiving the surrender of Damascus. After the death of Möngke he withdrew most of his army, and the force left behind was defeated by the Mamluks at Ain Jalut in September 1260. In 1261 the Mamluk sultan Baybars installed an Abbasid survivor as a figurehead caliph in Cairo.

Myths and facts

“The Tigris ran black with ink, then red with blood.” This vivid image comes from later tradition. Libraries certainly suffered, but the claim cannot be measured, and some institutions, such as the Mustansiriya madrasa, continued to function after 1258.

“The House of Wisdom was destroyed in 1258.” The House of Wisdom was famous in the 9th century, but historians doubt it still existed as a major institution in 1258. Baghdad’s surviving libraries, not one legendary academy, were what was lost.

“The caliph starved to death among his gold.” This story appears in Marco Polo’s account and in other moral tales. It is not supported by the main Persian and Arabic sources.

Timeline

• 1253: Hulagu sets out westward from Mongolia on Möngke’s orders.
• 1256, November: Ismaili leader Rukn al-Din Khurshah surrenders to Hulagu.
• 1258, mid-January: The caliph’s army is destroyed near Anbar after the Mongols flood its camp.
• 1258, 29 January: Baghdad is fully encircled and the siege begins.
• 1258, c. 4–5 February: Mongols take much of the eastern wall.
• 1258, 10 February: Caliph al-Musta’sim surrenders.
• 1258, c. 13 February: The sack of Baghdad begins.
• 1258, c. 20 February: Al-Musta’sim is executed.
• 1261: An Abbasid caliph is installed in Cairo by the Mamluks.

Why it matters

The siege of Baghdad marked the end of the classical Abbasid world and the high point of Mongol expansion in the Middle East. It reshaped the political map of Iraq and Iran, shifted the centre of Arab Muslim power to Mamluk Cairo, and remains a powerful symbol of loss in Islamic memory.