Mongol Frontiers, Garrisons and Fortified Places

From 1206 until the empire’s division around 1260, Mongol rulers extended authority across mobile pastoral lands and densely settled regions. A victorious army could pass through a district without administering it. Tribute and an appointed official created a more lasting presence; a garrison, a force stationed to hold a place, could support it. The form of control varied with local politics and military needs.

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From campaign to foothold in North China

The Jin dynasty, ruled by Jurchens, a people from northeastern Asia, governed much of northern China. Its capital Zhongdu stood at present-day Beijing. Mongol armies crossed the Jin frontier in 1211, overcame fortifications in Hebei, a region of northern China, and opened the route through Juyongguan, a strategic pass north of the capital. They plundered the countryside, then withdrew for the winter and returned to their northern pastures. Towns they had taken were reoccupied. The first campaign had disrupted Jin defenses and drawn defectors, but did not yet leave Mongol officials holding every captured place.

The sequence changed in 1213. Mongol forces recaptured the fortified pass and established a siege of Zhongdu. A siege meant surrounding a defended city and blocking relief and supplies until its defenders had to negotiate or surrender. In early 1214 the blockade ended after disease spread among Mongol troops and animals and the besiegers struggled with siege warfare. Jin emperor Xuanzong offered gold, silver, silk, horses and a princess in marriage for peace. Genghis Khan accepted and withdrew.

When the Jin court abandoned the devastated capital and moved south, Mongol forces renewed the blockade in autumn. Chinese and Khitan contingents, including soldiers from a people who had earlier ruled parts of northern China, now fought under Mongol command. Zhongdu surrendered in May 1215 after famine weakened the besieged population; it was sacked and burned, and Mongol officers inventoried the Jin treasury. The taking of the city created an administrative foothold that the earlier raids had not. The Jin state continued to resist elsewhere until its final defeat in 1234 under Genghis’s son Ögedei.

Chinese infantry and siege technicians from conquered communities helped the Mongols attack fortified places in China. By drawing on their expertise, commanders could approach a walled town as an objective instead of bypassing it. This is one part of the broader siege work that made expansion into settled regions possible.

Officials and garrisons

After Genghis Khan, the supreme Mongol ruler known as the Great Khan, returned to Mongolia in 1216, he left appointed representatives in conquered regions. One was Jaʿfar Khwaja, a merchant who had helped negotiate terms with the Jin. These officials, called darughachi, represented the khan and linked local government to Mongol authority. In 1217 Muqali became supreme commander in north China, based at Zhongdu, with Mongol troops alongside many Khitan and Chinese auxiliaries. The combination of a commander, appointed representatives and local forces made it possible to continue operations after the Great Khan and most of his army departed.

In Persia, roughly present-day Iran, officials called darughachi also administered towns while small garrisons remained in the countryside. Their recorded duties included assessing taxes, sending revenue and tribute to the court, maintaining the relay-post system, compiling population registers, recruiting local security forces and arranging official travel. Such duties made the garrison more than a guard at a gate: it connected military presence to the movement of money, messages, labour and people. The Persian evidence describes one regional practice rather than a single uniform arrangement for every Mongol territory.

Local resources and the cost of occupation

Mongol commanders kept experienced local officials in office and appointed others to help gather the resources needed for the Jin campaign. A title and tablet of authority could give a local appointee the power to issue orders. Hereditary lords who submitted brought their own forces, while local recruiters supplied additional soldiers. These arrangements let Mongol commanders draw on existing institutions and military experience instead of building an entire administration from scratch.

The demands were substantial. Civilians had to provide provisions and troops, especially for long blockades. War and displacement left some districts with weak central administration, and officials’ efforts to count households could not produce a reliable register in the midst of fighting. Local loyalties also shifted as rulers fell, officials changed sides and rebel leaders filled gaps in government. A fort or town therefore mattered through the people and supplies it could connect to a command, as well as through its walls.

Campaign reach and the western frontier

The Mongols’ withdrawal from Hungary in 1242 illustrates the difference between reaching a region and maintaining control there. Ulf Büntgen and Nicola Di Cosmo argued that unusually cold, wet conditions in early 1242 damaged mobility and reduced usable pasture. Zsolt Pinke and coauthors challenged that explanation, arguing that rain should have improved pasture and that the Mongols could sustain their herds. The environmental cause remains disputed.

Under Möngke, Genghis Khan’s grandson Hülegü led a major western expedition. His forces captured Alamut, a mountain stronghold in Iran, in 1256 and Baghdad in 1258. In 1260 they took Aleppo and Damascus in Syria. Hülegü withdrew toward Azerbaijan that spring, leaving a smaller force under Kitbuqa. The Mamluks defeated Kitbuqa at Ayn Jalut in September. Historians have proposed both the news of Möngke’s death and shortages of pasture and water as reasons for Hülegü’s withdrawal. The campaign briefly reached Syria, but the garrison left behind could not secure lasting Mongol control there.