Why Did the Mongol Empire Fall?


Posted by Bill Mattocks on Sunday, December 10, 2023

Mongol cavalry

The Mongol Empire was the largest contiguous land empire in history, spanning over 33 million square kilometers at its peak in the 13th century CE under the rule of Genghis Khan and his descendants (Weatherford). However, this mighty empire fragmented into four smaller khanates shortly after Kublai Khan’s death in 1294. What factors led to the disintegration of the once formidable Mongol realm? Several key reasons contributed to the empire’s decline by the 14th century CE.

Mongol Tradition of Division

The Mongols had a longstanding custom of dividing territories among the sons of a deceased khan to prevent internal strife. This policy was formalized during Genghis Khan’s reign as he split his lands evenly among his four sons (Weatherford). When Mongol leaders died, their domains were thus fractured into smaller, weaker factions. For instance, upon Genghis Khan’s death, Ögedei Khan became the Great Khan, but the Empire was divided into four regions ruled by Genghis’ sons (Allsen).

This tradition of fragmentation continued with successor khans. Möngke Khan designated his brother Kublai as heir, but when Möngke died in 1259 CE, another brother, Ariq Böke, claimed the title of Great Khan as well, sparking a civil war (Allsen). Such conflicts over succession plagued the empire, ultimately splintering Mongol territory.

Opposition to Kublai Khan

Statue of Kublai Khan

Kublai Khan founded the Yuan Dynasty in China after conquering the Song in 1279 CE. As he focused on governing China, he lost influence in the west, and hostile khans began brazenly attacking the frontiers of his holdings (Allsen). Kublai’s cousins in Central Asia strongly opposed him, rejecting his claim to authority over them. Beginning in the late 13th century, the Chagatai Khanate in Central Asia continuously launched massive invasions into Kublai’s lands. These constant costly wars depleted Mongol manpower and resources (Morgan).

Family infighting severely diminished unity, making the Mongols vulnerable to external foes. For example, Kaidu, the leader of the House of Ögedei, stoked resentment towards Kublai’s rule. From his stronghold in Central Asia, Kaidu led a powerful insurgency against Kublai while forging alliances with the Chagatai Khanate and the Golden Horde against the Yuan Dynasty for over 20 years. These rebellions occupied the Mongol military and persisted even after Kaidu died in 1301 CE, consuming resources and taxing Mongol stability (Allsen).

Overexpansion and Logistical Challenges

A prime reason for the Mongol Empire’s dissolution was that the territory under its control was simply too large to manage effectively. Transportation and communication were major challenges, even with the empire’s extensive pony express messaging system and well-built roads. With domains spanning from Eastern Europe to the Sea of Japan, khans struggled to assert control and project military strength across regions (Weatherford).

When Kublai conquered Southern Song China in 1279 CE, the swift victory led him to underestimate the difficulties of administrating the distant, rebellious lands. Overextension left the Yuan unable to fully defend its frontiers or subdue uprisings throughout China (Worthy). With decentralized rule, local Mongol leaders in Russia, Central Asia, and the Middle East lacked sufficient resources from the Great Khans to maintain firm control. By the late 1300s CE, Mongol dominion had effectively evaporated in most outlying areas (Weatherford).

Climatic Changes

Some scholars propose climate changes caused societal upheaval, weakening the Mongol Empire. Tree ring analysis indicates warmer, drier conditions prevailed in Inner Asia during the 13th century. However, the early 14th century brought a shift to a wetter, colder climate that reduced grasslands suitable for grazing Mongol herds (Pederson). Lacking pastureland, their livestock starved during harsh winters, forcing tribes to clash over scarce resources. There is evidence that desperate Mongol groups even resorted to raiding Chinese border settlements for sustenance when forage was unavailable (Zhang). This environmental stress and increased conflict may have strained the cohesion of the Mongols while enabling Chinese rebels to challenge their reign.

Spread of the Black Death

Painting of Black Death victims

In the mid-14th century CE, the bubonic plague, also called the Black Death, annihilated millions across Asia and Europe. As Mongols moved west along trade routes, they carried plague-infested fleas which fomented a massive epidemic. As much as a third to half of China’s population died, decimating the Mongol court and military ranks (Weatherford).

This catastrophic loss of Mongol elites and fighting forces weakened Yuan influence in China. Peasant rebels like the Red Turbans surged across the landscape, toppling Mongol regional rulers. By 1368, just 84 years after its formation, the Red Turbans completely expelled the Mongols, establishing the Ming Dynasty (Worthy). The plague similarly depleted the Ilkhanate Mongols in Persia, enabling local groups to revolt. From India to Russia, the Black Death was instrumental in inciting anticolonial movements that pushed out Mongol overseers left vulnerable by the disease.

Loss of Trade Revenue

Booming international trade enabled the 13th century Mongol political economy to underwrite military garrisons and government spending. The secure routes of the Pax Mongolica facilitated vibrant commerce between China, Persia, and Europe. But as the Mongols lost territory across Eurasia in the 1300s and 1400s CE, trade networks collapsed. This sharp reduction in custom tax income severely constrained funding for Mongol armies and administration. With depleted funds and weakened forces, the Mongols retreated (Weatherford). The prosperous world system of the Pax Mongolica unraveled into isolationist kingdoms in the late Middle Ages (Morgan).

Acculturation of Mongol Elite

As the Mongols ruled sedentary peasant societies in China, Persia, and Russia for generations, their nomadic warriors increasingly abandoned traditional ways, settling in cities and adopting local customs. By the 15th century CE, they were culturally assimilated peoples uninterested in reviving old Mongol imperial ambitions (Weatherford). For instance, descendants of Genghis Khan in Moghulistan degenerated into obscure tribes practicing shamanism, while Chagatai khans converted to Islam like their subjects. The core fighting spirit faded as they enjoyed urban living (Morgan). Over generations, Mongol khans and nobles assimilated with local populations such as Han Chinese and Uzbeks. They essentially ceased to exist as a distinct imperial force retaining aspirations of unified Mongol rule in the 15th century CE (Worthy).

Rise of New Empires

The Mongols not only struggled with internal strife and economic shifts in the 14th century, but faced the ascent of powerful new adversaries. As descendant groups like the Il-Khans and Chagatai fragmented, the Ottoman Empire and Mamluk Sultanate expanded in the Middle East. These robust, aggressive kingdoms rolled back Mongol influence in Anatolia and Iraq. Meanwhile, the Ming Dynasty expelled the Yuan rulers from China in 1368 CE and pursued an expansionist campaign to drive Mongols from the old Yuan frontiers (Weatherford).

With Mongol dominion squeezed by the Ming from the southeast, Timur’s surging empire from the west, and post-Kievan Russian princedoms from the north, their shrinking domains soon fractured into four main khanates (the Northern Yuan, Chagatai Khanate, Ilkhanate, and Golden Horde). Bereft of manpower, wealth, internal cohesion, and cosmopolitan vision, these small khans lacked the capacity to recreate the Pax Mongolica world system or reunite Genghis Khan’s empire in the 15th century CE (Allsen). They were relegated to the sidelines of Eurasian history.


In conclusion, the Mongol Empire dissolved just over a century after Genghis Khan’s death due to a confluence of factors. Factional wars over succession exhausted resources and unity. Logistical strains arising from administering immense territory ultimately overextended imperial control. Climatic fluctuations disrupted nomadic herding patterns while the Black Death plague toppled the leadership ranks of Mongol khans. The loss of overland trade hobbled revenues to maintain army garrisons. As generations passed, Mongol rulers assimilated with local cultures and lost their expansionist vision. Finally, the transition of power to aggressive new empires in Asia squeezed the Mongols from all sides. While the Mongol Empire shocked the medieval world during its heyday, it fragmented under the pressures of instability, disease, climate stress, economic shifts and rising power competitors into merely a memory of faded glory rather than an enduring world dominion by 1400 CE.

Frequently Asked Questions

What internally weakened the Mongol Empire?

Several key internal issues undermined Mongol imperial unity. Their tradition of splitting territory among sons of each deceased khan led to continuous infighting after Genghis Khan’s death in 1227 CE. Ever-fresh succession disputes caused civil wars and broke up Mongol lands. Overexpansion also left them unable to manage their immense realm.

How did external enemies contribute to the Empire’s decline?

As the unified Mongol state fractured after 1294 CE, breakaway Central Asian khans launched invasions that exhausted the Yuan Dynasty’s resources in repeated border wars. New expanding empires like the Ottoman, Mamluk, Ming Dynasty, and Timur’s realms ultimately squeezed the Mongols militarily and seized their territories.

What environmental factors played a role in weakening the Empire?

In the 14th century CE, climate changes produced colder, wetter weather that disrupted nomad patterns and living conditions, prompting Mongol groups to fight over scarce forage. Overgrazing also degraded the steppes that sustained pastoral herding. This strained the social fabric and fighting capacity of the Mongols.

How did economics impact Mongols’ ability to maintain control?

Booming overland trade enabled the 13th century Pax Mongolica system, financing Mongol armies and administration via taxes on commerce. However, the breakdown of Mongol authority across Eurasia severed overland trade networks by the 15th century. The resulting loss of trade revenue critically reduced funds to defend their declining empire.

Why did Mongol rulers assimilate and abandon traditional ways?

As Mongol elites ruled foreign lands for generations like China, Persia, and Russia, they increasingly adopted local cultures and lifestyles. For example, they converted to Islam in Persia, while intermarrying with Chinese nobility and settling in cities. Their fighting skills, mobility, and ambition to control trade routes steadily dissipated as khans “went native.”