The Mongol Empire

Origins

The Mongol Empire was founded by Temüjin, born around 1162 to the chief of a minor Mongol clan in the steppe region of northern Mongolia. His father was poisoned when Temüjin was approximately nine years old, leaving his family in destitution. Over the following three decades Temüjin built, by a combination of personal charisma, military innovation, calculated political marriages, and methodical destruction of his rivals, the unified Mongol confederation. He was acclaimed Genghis Khan — “Universal Ruler” — at a council of the Mongol tribes (the kurultai) in 1206. He was approximately 44 years old.

The military system Genghis Khan created over the following twenty years was the most effective force in the medieval world. Its key elements were: a decimal organization (units of 10, 100, 1,000, and 10,000); promotion strictly by merit rather than birth; the use of mounted archers as the primary tactical arm, with each soldier maintaining a string of three to five remounts; the integration of conquered local infantry and engineering corps; a sophisticated reconnaissance and intelligence system; and the strategic use of psychological terror — the systematic destruction of cities that resisted, balanced against the relative leniency offered to those that surrendered.

The conquests under Genghis

Genghis Khan’s lifetime conquests, between 1206 and his death in 1227, encompassed:

• The Tangut Xi Xia state (northwestern China), conquered 1209–1227.
• The Jin dynasty (northern China), invaded from 1211; Beijing fell in 1215.
• The Kara-Khitan Khanate (central Asia), conquered 1218.
• The Khwarazmian Empire (Iran, Afghanistan, Transoxiana), conquered 1219–1221 in the most destructive single campaign of the medieval period. The cities of Bukhara, Samarkand, Merv, Nishapur, and Herat were systematically destroyed; the population losses across the affected region have been estimated by some historians at 30–50 percent.
• The Caucasian and southern Russian steppe, raided 1220–1223.

Genghis Khan died in August 1227, aged approximately 65, on campaign against the Xi Xia. The cause of death is uncertain — variously reported as falling from a horse, an unidentified illness, or wounds in battle. He was buried in an unmarked grave in northern Mongolia. The location has never been identified.

The successors

The empire continued to expand for fifty years after Genghis Khan’s death. His sons and grandsons divided the empire administratively while maintaining ultimate political loyalty to the Great Khan at the central court in Karakorum (later Beijing). The major successor conquests were:

• The destruction of the Russian principalities by Batu Khan, 1237–1240; Kiev was sacked in December 1240 and would not regain its pre-conquest population for centuries. The Golden Horde (the western Mongol khanate) ruled the Russian principalities until 1480.
• The invasion of Hungary and Poland, 1241–1242. The Mongol army defeated the combined Hungarian-Croatian forces at Mohi and the combined Polish-German forces at Legnica. Western Europe was open. The Mongols withdrew east in April 1242 on news of the death of the Great Khan Ögedei, to participate in the succession kurultai. They never returned to central Europe.
• The destruction of the Abbasid Caliphate by Hulagu Khan, 1258. Baghdad was sacked in February 1258; the caliph al-Musta’sim was rolled in a carpet and trampled by horses. The library of the House of Wisdom, the largest in the medieval Islamic world, was destroyed; the Tigris was reported by contemporaries to have run black with ink from books thrown into it.
• The completion of the conquest of China by Kublai Khan, 1271–1279. Kublai established the Yuan dynasty in 1271 and completed the conquest of the Southern Song in 1279, unifying China under Mongol rule.

The empire reached its greatest extent around 1279. It stretched from the Pacific to the Black Sea, encompassed approximately 24 million square kilometres, and ruled approximately 110 million people.

Fragmentation

The empire began to fragment from 1260 onwards. The successor states — the Yuan dynasty (China and Mongolia), the Ilkhanate (Iran, Iraq, Anatolia), the Chagatai Khanate (central Asia), and the Golden Horde (Russia and the western steppe) — operated as independent polities by 1280 and were sometimes in open warfare with each other. The Mongol-on-Mongol Battle of Köse Dağ (1243) had already produced an effective Ilkhanate-Golden Horde split; subsequent succession crises across the four khanates produced complete political fragmentation.

The Yuan dynasty in China fell to the Han Chinese Ming dynasty in 1368, after a century of governing China. The Ilkhanate in Persia collapsed into civil war in 1335 and was succeeded by smaller Turco-Mongol states. The Chagatai Khanate split into eastern and western successor states in the 1340s. The Golden Horde ruled the Russian principalities until Ivan III of Moscow successfully refused to pay tribute in 1480. Crimean and Kazan successor khanates survived into the 18th century before being absorbed by the Russian Empire.

Consequences

The Mongol conquests killed, by conservative modern estimates, approximately 40 million people across the Eurasian landmass — a sustained mortality comparable proportionally to the Black Death of the following century. The conquered regions of central Asia and Persia did not recover their pre-conquest population for centuries. The destroyed cities of Khwarazm were not rebuilt; the irrigation systems of Khorasan were not maintained; the economic infrastructure of medieval Iran was set back by approximately 200 years.

The empire also produced one of the great periods of Eurasian connectivity. The Pax Mongolica — the period of safe travel across the empire from approximately 1240 to 1340 — produced the first sustained European-East Asian commercial and intellectual contact in the historical period. Marco Polo’s travel narrative of 1271–1295, Ibn Battuta’s somewhat later Eurasian travels, and the eastern transfer of gunpowder, the compass, paper money, and printing technology from China to the West all happened within the Pax Mongolica. The disease that became the Black Death was almost certainly also transmitted along Mongol-era trade routes: recent genomic work locates the proximate origin of the 14th-century Yersinia pestis strain in the Tian Shan mountains of central Asia, in the heart of the Chagatai Khanate.

The Mongol political tradition shaped subsequent Eurasian state-building. The Ottoman, Mughal, Safavid, and Romanov dynasties all incorporated elements of Mongol administrative practice — the post-station system (yam), the population census, the silver-tribute economy, the universal-emperor political theology — that the Mongols had themselves inherited and adapted from the Chinese and Persian traditions they had conquered.

Modern Mongolia is a parliamentary republic of approximately 3.4 million people. The Genghis Khan equestrian statue at Tsonjin Boldog, built 2008, is the largest equestrian statue in the world.