Repercussions

At its height the Mongol Empire stretched from the Sea of Japan to the Carpathians and from the Siberian forests to the Persian Gulf — some 24 million square kilometers, the largest contiguous land empire the world has ever seen, ruling over perhaps a quarter of the human race. It brought under a single political order an astonishing diversity of peoples, religions, and civilizations, from Confucian China to Orthodox Russia to the Islamic Middle East, an achievement of conquest and administration without parallel before or since.

By uniting the length of the Silk Road under one authority, the Mongols created a century of relative peace and safety — the Pax Mongolica — in which merchants, missionaries, and travelers could cross Eurasia as never before. Protected caravan routes and an efficient relay-courier system (the yam) knit the continent together, and figures like Marco Polo traveled from Europe to the court of Kublai Khan. Goods, technologies, and ideas flowed in both directions in an unprecedented age of long-distance exchange.

The same trade networks that carried silk and silver across Eurasia also carried disease. The Black Death — the catastrophic plague pandemic of the mid-fourteenth century — is widely thought to have spread westward along the Mongol-secured trade routes from Central Asia, reaching the Crimea (where, by tradition, it was catapulted into a besieged Genoese port) and from there ravaging the Middle East and Europe. The pandemic killed perhaps a third of Europe's population and reshaped the late medieval world — an unintended and devastating consequence of Eurasian integration.

The sack of Baghdad in 1258 — with the destruction of its libraries, the slaughter of its scholars and population, the ruin of Mesopotamia's ancient irrigation, and the extinction of the Abbasid Caliphate — is frequently marked as the end of the Islamic Golden Age. The center of Islamic civilization was shattered, and the wider Mongol devastation of the Iranian world wrecked cities and learning that had flourished for centuries. Though Islamic culture endured and the Mongols' own Ilkhanate rulers eventually converted to Islam, the catastrophe left a lasting wound in the civilization's memory.

For roughly 240 years the Russian principalities lived under the overlordship of the Golden Horde — the 'Tatar Yoke' — paying tribute and deferring to the khans at Sarai. The experience profoundly shaped Russia: it isolated the Rus from western Europe, and it elevated the once-minor town of Moscow, whose princes rose to power as the Horde's favored tax-collectors and gradually gathered the Russian lands under their rule. Many historians trace features of later Russian autocracy to this long subjection, and Russia's eventual overthrow of the Horde gave birth to the expanding Muscovite state.

The unified empire did not long outlast its founders. By the late thirteenth century it had divided into four great khanates — the Yuan dynasty in China and Mongolia, the Ilkhanate in Persia, the Chagatai Khanate in Central Asia, and the Golden Horde in Russia and the western steppe — increasingly independent, culturally distinct, and often at war with one another. Each absorbed the civilization it ruled: the Yuan became Chinese, the western khanates Islamic. The dream of a single Mongol world-empire dissolved, though its successor states dominated their regions for generations.

The Mongol unification of Eurasia accelerated the transmission of technologies, goods, and knowledge between civilizations on a vast scale. Chinese inventions — including gunpowder, printing, and the compass — spread westward; administrative, medical, astronomical, and artistic knowledge moved between China, Persia, and beyond; and the Mongols themselves deliberately gathered and resettled skilled artisans and scholars from across their domains. This great circulation helped seed developments — not least the spread of gunpowder weaponry to Europe — that would transform the wider world.

In China, the Yuan dynasty founded by Kublai Khan declined through the fourteenth century amid factional strife at court, financial crisis, devastating floods and famine, plague, and a series of popular rebellions. In 1368 the rebel leader Zhu Yuanzhang drove the Mongols out of China and founded the native Ming dynasty, while the Yuan court retreated to the steppe as the rump 'Northern Yuan.' The expulsion ended Mongol rule over the most populous land on earth and confirmed that the age of Mongol world-conquest had passed into history, leaving the Mongols once again a steppe power.