Why Did the Mongols Start Their Conquest?: Looking Into What Motivated Them to Expand


Posted by Julian Wymanton on Saturday, February 10, 2024

The rise of the Mongol Empire in the 13th century CE is one of the most rapid and extensive conquests in human history. At its height, the Mongol Empire stretched from Eastern Europe to the Sea of Japan, making it the largest contiguous land empire ever. But what drove the nomadic Mongol tribes to leave their homeland in the steppes of Central Asia and embark on a campaign of conquest that subjugated most of Eurasia? There were several intertwining factors that motivated the Mongols’ conquests:

Economic and Demographic Factors

The Mongol economy was based on pastoral nomadism and raiding. However, in the early 13th century, a combination of economic and demographic stresses built up that compelled them to look outward for plunder and conquest:

  • Climate Change: Tree ring data indicates that the steppe lands experienced a drought in the early 1200s. This reduced grasslands for livestock grazing, putting strain on the Mongols’ pastoral lifestyle.

  • Overpopulation: The Mongol population was growing and there were limited resources to support them. There may have been intra-Mongol battles for scarce resources.

  • Increased Warfare: Competition for grazing land and pressure from neighboring tribes caused more frequent warfare between nomadic confederations in the steppes during this time. This honed the Mongols’ martial skills.

These strains gave Mongol leaders like Genghis Khan incentives to attack the sedentary civilizations to their south and west to gain war spoils to distribute among their followers. It was a way to alleviate resource shortages and demographic pressures. Conquest also gave them new grazing lands.

Mongol warrior on a horse

Political Factors

In the late 12th century CE, a chieftain named Temüjin – later Genghis Khan – united the Mongol tribes into a confederation after decades of intertribal warfare. He created a disciplined cavalry force and masterful military strategy that could overwhelm opponents – inspiring the still-fractured Mongols with a vision to become “rulers of all under heaven.”

After securing control over the Mongolian Plateau around 1206 CE, Genghis Khan sent raiding parties and diplomatic missions to the Jin Dynasty of northern China and the Khwarezm Empire in Central Asia:

  • When the Khwarezm Shah had Mongol envoys executed in 1218 CE, it gave Genghis a pretext to invade Central Asia as retaliation the following year. This began the Mongols’ conquests in earnest.

  • In 1234, the Great Khan Ögedei resumed the invasion of the Jin Dynasty his father Genghis had started – completing its destruction by 1234 CE. This gave the Mongols control of northern China and a base for further eastern conquests.

The early successes against these empires demonstrated that conquest could bring riches, grazing lands, and glory. This inspired the later Khans to continue expanding Mongol domains.

Mongolia wild horses

Ideological Factors

The stability of Mongol rule depended partly on continually rewarding followers with spoils and conquests. If opportunities for plunder dried up, there was a risk chieftains would rebel or splinter off – reversing Mongol unity.

There was also an emergent Mongol imperial ideology driving expansion. After each new victory, the Khans became more convinced it was their divine mandate to rule “all quarters” – putting pressure on successive leaders to find new campaigns in order to live up to this growing sense of destiny.

The Mongols practiced systematic terror on cities that resisted them as psychological warfare to intimidate others into immediate surrender – saving Mongol lives, speeding up conquest, and enhancing their fearful reputation. Massacres like at Baghdad in 1258 CE terrified other regions into capitulating, accelerating conquests further west.

Military Factors

The Mongols had several key military advantages that facilitated their conquests:

  • Disciplined Cavalry: The Mongols perfected nomadic cavalry warfare – coordinatingmounted archers to outmaneuver and confuse opponents. Cavalry gave them mobility over large distances.

  • Composited Bows: Mongols used specialized bows made from bone, horn, and sinew that had longer range, accuracy, and penetration than typical wooden bows of sedentary armies. This gave them an edge in battles.

  • Adapted Siege Tactics: The Mongols systematically captured and incorporated siege engineers from conquered regions to develop technologies like trebuchets to reduce cities and fortresses protecting transcontinental trade routes.

  • Military Meritocracy: The Mongols were more meritocratic than feudal kingdoms, rewarding officers based on ability rather than class or birth. This meant competent generals led Mongol expansion.

The combination of mobile cavalry, improved weaponry, advanced siegecraft, and tactical prowess allowed the Mongols to sweep through Eurasia by exploiting weaknesses in fragmented kingdoms.

Mongol Empire raid

Conclusion: Why Did the Mongols Expand?

The Mongols’ eruption from their isolated steppe homeland to forge the largest land empire in history can be attributed to the interplay between environmental stressors, the leadership of chieftains like Genghis Khan, the nomadic cavalry military system, and the emerging ideology of Mongol manifest destiny. Conquest offered relief from resource shortfalls while increasing Mongol power and prestige. Once the expansionist pattern was entrenched, the need to maintain the loyalty of subordinates by providing them plunder created its own motivation for further conquests by Genghis Khan’s descendants. Superior tactics and adaptation of foreign technologies for siege warfare facilitated the rapidity at which the Mongols subdued most sedentary civilizations across Asia and Europe within a couple generations – establishing an empire of unprecedented scale.

Works Cited

“Genghis Khan.” Ancient History Encyclopedia, Ancient History Encyclopedia, 28 Jan 2022, https://www.ancient.eu/Genghis_Khan/. Accessed 10 Feb 2023.

Morgan, David. The Mongols, 3rd ed., Wiley-Blackwell, 2019.

Weatherford, Jack. “Why the Mongol Conquests Mark an Inflection Point in World History.” AHA Today, American Historical Association, 8 May 2015, https://www.historians.org/publications-and-directories/perspectives-on-history/may-2015/why-the-mongol-conquests-marked-an-inflection-point-in-world-history. Accessed 10 Feb 2023.

Frequently Asked Questions

What was the climate like when the Mongols started expanding?

Tree ring data shows evidence of drought affecting the Mongolian steppe lands in the early 1200s CE. This reduced grasslands available for the Mongols’ livestock herds, causing economic pressures.

How did Genghis Khan unite the Mongol tribes?

After emerging victorious from years of intertribal warfare, Genghis Khan united the rival Mongol confederations around 1206 CE following his election as Khan. He implemented reforms that organized the tribes into a unified military state.

What role did weather play in Chengis Khan’s conquest?

Drought conditions in the early 13th century made the traditional Mongol pastoral lifestyle harder to sustain, leading to scarce resources and warfare over grazing territory. Uniting to raid neighboring civilizations offered climate relief.

How did the execution of Mongol envoys lead to invasion?

When the Khwarezm Shah had Genghis Khan’s envoys and merchants executed rather than establish trade, it angered the Khan and gave him a justification to launch a full invasion of the Khwarezm Empire in 1219 CE with an eye toward full conquest.

Why were the Mongols able to conquer so many territories across Asia and Europe?

The Mongols’ fast conquests stemmed from the mobility of their large cavalry units to travel immense distances quickly, more advanced bows and adapted siege engines, and greater tactical coordination. These overwhelmed fragmented realms before they could form unified resistance efforts against the common foe.