Siege of Bukhara in the context of "Mongol conquest of Persia"

The Mongol conquest of Persia and Mesopotamia comprised three Mongol campaigns against Islamic states in the Middle East and Central Asia between 1219 and 1258. These campaigns led to the termination of the Khwarazmian Empire, the Nizari Ismaili state, and the Abbasid Caliphate of Baghdad, and the establishment of the Mongol Ilkhanate government in their place in Persia.

Genghis Khan had unified the Mongolic peoples and conquered the Western Xia state in the late 12th and early 13th centuries. After a series of diplomatic provocations on the part of Muhammad II, the ruler of the neighbouring Khwarazmian Empire, the Mongols launched an invasion in 1219. The invaders laid waste to the Transoxianan cities of Bukhara, Samarkand, and Gurganj in turn, before obliterating the region of Khorasan, slaughtering the inhabitants of Herat, Nishapur, and Merv, three of the largest cities in the world. Muhammad died destitute on an island in the Caspian Sea. His son and successor, Jalal al-Din, tried to resist the Mongols, but was defeated and forced into exile. Genghis returned to his campaign against the Jin dynasty in 1223, only retaining governance of the northern Khwarazmian regions.

Between 1219 and 1221, the Mongol forces under Genghis Khan invaded the lands of the Khwarazmian Empire in Central Asia. The campaign, which followed the annexation of the Qara Khitai Khanate, saw widespread devastation and atrocities. The invasion marked the completion of the Mongol conquest of Central Asia, and began the Mongol conquest of Persia.

Both belligerents, although large, had been formed recently: the Khwarazmian dynasty had expanded from their homeland to replace the Seljuk Empire in the late 1100s and early 1200s; nearly simultaneously, Genghis Khan had unified the Mongolic peoples and conquered the Western Xia dynasty. Although relations were initially cordial, Genghis was angered by a series of diplomatic provocations. When a senior Mongol diplomat was executed by Khwarazmshah Muhammed II, the Khan mobilized his forces, estimated to be between 90,000 and 200,000 men, and invaded. The Shah's forces were widely dispersed and probably outnumbered—realizing his disadvantage, he decided to garrison his cities individually to bog the Mongols down. However, through excellent organization and planning, the Mongols were able to isolate and conquer the Transoxianan cities of Bukhara, Samarkand, and Gurganj. Genghis and his youngest son Tolui then laid waste to Khorasan, destroying Herat, Nishapur, and Merv, three of the largest cities in the world. Meanwhile, Muhammed II was forced into flight by the forces of Mongol generals Subutai and Jebe; unable to reach any bastions of support, he died destitute on an island in the Caspian Sea. His son and heir Jalal-al Din managed to mobilize substantial forces, defeating a Mongol general at the Battle of Parwan, but these were crushed by Genghis at the Battle of the Indus a few months later.

The siege of Samarkand took place in March 1220 after Genghis Khan, founder of the Mongol Empire, had launched a multi-pronged invasion of the Khwarazmian Empire, ruled by Shah Muhammad II. The Mongols had laid siege to the border town of Otrar, but finding its defences obdurate, a large force commanded by Genghis and his youngest son Tolui detached from the vanguard and set off southwards, towards Transoxiana.

Samarkand was the Shah's capital and the pivot of his defence — the city's garrison was large and its battlements were one of the strongest in the empire. Genghis, however, managed to isolate it by capturing and destroying Bukhara in a surprise manoeuvre, and then laying waste to the nearby Transoxianan towns. After repelling relief forces, the Mongol army, now reinforced after the capture of Otrar, ambushed and massacred a sortie by the town's defenders. The citizens of the city soon surrendered at the instigation of the Muslim clergy; most were however enslaved or conscripted in traditional Mongol fashion.

The siege of Gurganj occurred during the Mongol invasion of the Khwarazmian Empire. The siege's length is variable, with historians such as Rashid al-Din Hamadani stating that it lasted for seven months, but it is largely agreed that it ended with the defeat and annihilation of the city in April 1221. Genghis Khan, ruler of the Mongol Empire, had launched a multi-pronged assault on the Khwarazmian Empire, ruled by Shah Muhammad II. Through a combination of efficient planning and excellent manoeuvering, the Khan's army managed to take the border town of Otrar swiftly, followed by the large cities of Bukhara and Samarkand. The siege, among others, was witnessed by the Persian biographer Shihab al-Din Muhammad al-Nasawi, who recorded an account in Arabic c. 1241.

Genghis sent a detachment, led by his sons Jochi and Chagatai, northwest to lay siege to the former capital of Gurganj. Immensely wealthy, the city lay on marshy grounds on the delta of the Amu Darya, making it difficult to assault. Adapting to the lack of stones to use as projectiles, the Mongols cut down huge groves of mulberry trees, soaked the trunks in water to harden them, and used them as battering rams and catapult projectiles.