The siege warfare of the Mongols was one of the most important factors in the success of the Mongol conquests. The Mongols were not, at the beginning of their conquests, expert at siege warfare, but they quickly learned the art from the Chinese and the Muslims. The Mongols recruited engineers and craftsmen from the conquered peoples, and they used a wide variety of siege weapons, including catapults, ballistas, and (after the conquest of the Song Dynasty) gunpowder weapons.
The Mongol siege warfare was, in many ways, a synthesis of Chinese and Islamic military technology. The Mongols adopted the Chinese trebuchet and the Islamic mangonel, and they combined these weapons with their own techniques of cavalry warfare. The combination gave the Mongols a decisive advantage in siege warfare, and it was one of the keys to the success of the Mongol conquests.
The Early Period: Limited Siege Capabilities
In the early years of the Mongol conquests, the Mongols had limited capabilities in siege warfare. The traditional steppe army was based on the use of mounted archers, and the Mongols had little experience in attacking fortified cities. The early Mongol campaigns were therefore focused on the open steppe, where the Mongol horse had a decisive advantage, and on the smaller cities and fortresses of the steppe, which could be taken by storm or by blockade.
The first major siege that the Mongols attempted was the siege of Zhongdu (modern Beijing) in 1215. The siege was a long, difficult affair, and the Mongols were eventually forced to withdraw. The defeat at Zhongdu was a major setback for the Mongols, and it taught them the importance of siege warfare. The Mongols responded by recruiting Chinese engineers and craftsmen, and they used these engineers to develop a new generation of siege weapons.
The siege of Zhongdu was a turning point in the history of Mongol siege warfare. The Mongols learned that they could not conquer the major cities of China without better siege weapons, and they began to invest heavily in the development of these weapons. The investment paid off handsomely in the following decades, as the Mongols developed a sophisticated siege capability that was unmatched by any of their enemies.
The Adoption of Chinese Technology
The Mongols adopted a wide variety of Chinese siege technologies, including the trebuchet, the ballista, and the siege tower. The most important of these was the trebuchet, a large counterweight catapult that could hurl heavy stones at the walls of a besieged city. The trebuchet was a Chinese invention, and it had been used in China for centuries before the Mongol conquest. The Mongols adopted the trebuchet in the early thirteenth century, and they used it with devastating effect in the sieges of Bukhara, Samarkand, and Merv.
The Mongols also adopted the Chinese siege tower, a tall wooden structure that could be moved up to the walls of a besieged city. The siege tower was used to allow the attackers to shoot down on the defenders, and it was a major advantage in attacking fortified cities. The Mongols also adopted the Chinese battering ram, a heavy log that could be swung against the gates of a city.
The Adoption of Islamic Technology
The Mongols also adopted a wide variety of Islamic siege technologies, including the mangonel, the arbalest, and the petrary. The most important of these was the mangonel, a torsion-powered catapult that could hurl stones or incendiaries at the walls of a besieged city. The mangonel was an Islamic invention, and it had been used in the Middle East for centuries before the Mongol conquest. The Mongols adopted the mangonel in the early thirteenth century, and they used it with devastating effect in the sieges of Baghdad, Aleppo, and Damascus.
The Mongols also adopted the Islamic arbalest, a powerful crossbow that could shoot bolts with great force and accuracy. The arbalest was a major advantage in attacking fortified positions, and it was widely used by the Mongol armies in the Middle East. The Mongols also adopted the Islamic petrary, a type of sling that could hurl stones with great force and accuracy.
The Use of Gunpowder
The Mongols were also among the first to use gunpowder weapons in warfare. The Chinese had developed gunpowder in the ninth century, and the Mongols adopted the technology after the conquest of the Song Dynasty in southern China. The Mongols used gunpowder weapons in a wide variety of ways, including fire lances, bombs, and rockets.
The most famous of the Mongol gunpowder weapons was the huo pao, or “fire bomb,” a ceramic or metal shell filled with gunpowder and shrapnel. The huo pao was used to attack fortified positions, and it was a major advantage in siege warfare. The Mongols also used the huo chong, a kind of gunpowder-powered fire lance that could project a jet of flame at the enemy.
The use of gunpowder weapons was a major innovation of the Mongol military, and it was one of the ways in which the Mongols helped to spread military technology across Eurasia. The use of gunpowder weapons was eventually adopted by the armies of the Middle East and Europe, and it was one of the factors that led to the development of the modern firearms.
The Mongol Siege Engineers
The Mongol siege engineers were among the most skilled in the medieval world. The engineers were drawn from the conquered peoples, particularly the Chinese, the Muslims, and the Christians, and they were responsible for the design, construction, and operation of the siege weapons. The engineers were highly valued by the Mongol commanders, and they were often given positions of considerable authority in the army.
The most famous of the Mongol siege engineers was Guo Kan, a Chinese engineer who served under Genghis Khan and who was responsible for the design of the siege weapons used in the conquest of the Khwarezmian Empire. Guo Kan was reportedly a brilliant engineer, and he was credited with the design of the trebuchets that were used in the sieges of Bukhara and Samarkand. Guo Kan was eventually killed in battle, but his legacy lived on in the siege weapons of the Mongol army.
The other major siege engineers included Ala al-Din, a Muslim engineer who served under Hulagu and who was responsible for the design of the siege weapons used in the sack of Baghdad; and Ismail, a Syrian engineer who served under the Ilkhanate and who was responsible for the design of the siege weapons used in the conquest of Syria.
The Legacy of the Mongol Siege Warfare
The Mongol siege warfare was one of the most important factors in the success of the Mongol conquests, and it was a major contribution to the history of military technology. The adoption of Chinese and Islamic siege technologies, the use of gunpowder weapons, and the recruitment of skilled engineers from the conquered peoples all helped to make the Mongol army the most effective siege force in the medieval world. The legacy of the Mongol siege warfare is still visible in the modern world, particularly in the use of gunpowder weapons, which the Mongols helped to spread from China to the Middle East and Europe.
Sources
- Timothy May, The Mongol Art of War (Barnsley: Pen & Sword, 2007), ch. 6.
- David Morgan, The Mongols (2nd ed., Oxford: Blackwell, 2007), ch. 3.
- John Man, Genghis Khan: Life, Death and Legacy (London: HarperCollins, 2004), ch. 11 — for the siege of Samarkand 1220 and Bukhara 1220.
- Stephen R. Turnbull, Mongol Warrior 1200–1350 (Oxford: Osprey, 2003).
- George Lane, Early Mongol Rule in Thirteenth-Century Iran: A Persian Renaissance (London: RoutledgeCurzon, 2003) — for the Ilkhanid siege traditions.