Driving their enemies before them

The Mongol Empire (1206–1368) was a world-altering force. Armies of horsemen thundered across seas of grass. They left devastation in their wake, committing acts of violence so horrific, entire cities surrendered in the hope of mercy. As he directed the sacking of the world’s greatest cities, the Mongols’ great conqueror, Genghis Khan, warned his victims: “I am the punishment of God.”

But why focus on the sensational accounts of the Mongol armies sweeping across Eurasia as though they were in an action film, when we can talk about merchants, physicians, administrators, and some guys who really liked to look at stars?

Woo! Yeah! Astronomers! Doctors! Bureaucrats! Let’s go!

The world conqueror

Don’t worry, we’ll talk a bit about the conquests and armies. Because they’re important too. To understand the Mongols’ impact on the world, you first need to understand how they managed to conquer most of that world.

The Mongol Empire was huge. It was the largest empire in history, covering over 17 percent of the world’s landmass and ruling a quarter of the global population. Its borders stretched from Korea to Hungary. Today, 28 countries have territory that was once ruled by the Mongol Empire. And it could have been even bigger. At the edges of their empire, the Mongols launched two failed invasions of Japan, thwarted both times by typhoons and samurai armies. The Mamluks in Egypt managed to prevent the Mongol conquest of the entire Islamic world. The Delhi Sultanate frustrated their attempts to take India. Other unsuccessful invasions of Eastern Europe and Southeast Asia also limited Mongol conquest.

Murder mystery on the steppes

At the dawn of the thirteenth century, the Mongols were unlikely empire builders. They were a loose collection of tribes on the steppes north of China. The Eurasian steppe is a band of dry grassland stretching from Eastern Europe to East Asia. The Mongols lived in semi-nomadic, pastoralist communities. Their populations were low, and they were politically decentralized. Though they valued trade, the Mongols lived on the edge of the major Afro-Eurasian trade networks. Their production was generally small scale and they sold their goods only to their neighbors. And yet, the Mongol Empire would conquer and reshape the world for 150 years. How did these divided tribes come to conquer and rule the world’s largest contiguous empire?

Solving this question is like solving a murder mystery. We need a motive, a weapon, and an opportunity. The motive in this case is maybe a little surprising: climate change. Historians believe that an intense drought in the late twelfth century shriveled the pasture lands that the Mongols’ herds relied on. This drove the tribes farther south, where they raided agricultural societies. As for weapons, the Mongol Empire had two very important advantages. The first was their mastery of horse warfare. Mongol men and women were exceptional riders, and they perfected cavalry tactics.

Their second weapon was a leader: Genghis Khan.¹ Named Temujin at birth, he was still a boy when his father was killed. Life got even harder as many of his tribe abandoned him, and he was captured by a rival. But Temujin managed to escape and win new followers to his side. His abilities as a military leader won him victories and allies. By 1206, he united the disparate tribes of the steppes into a confederation. A council of chiefs renamed Temujin Genghis Khan—meaning “universal emperor.”

After his remarkable feat of uniting the tribes, Genghis seized his opportunity, and he and his successors launched one of the largest campaigns of conquest the world has ever seen. While growing, however, the Mongol Empire became too big for one person to rule. Over the course of the thirteenth century, it was gradually divided into four khanates:

1. The khanate of the Great Khan, centered in Mongolia and China (after 1279 known as the Yuan dynasty)
2. The Chagatai khanate, in Central Asia
3. The Ilkhanate, in Persia
4. The khanate of the Golden Horde, in the northwest

For a time, the Great Khan in the east ruled over the others, but eventually, the various khans came into conflict, and their power was diminished. Still, for over a century after his death, the successors of Genghis Khan dominated Eurasia.

The networks of Mongol rule

Managing an empire of nine million square miles was no easy thing. But the Mongols’ remarkably open society helped. Trade was central to the khans’ power. By maintaining order across the Silk Roads, they repressed bandits and encouraged the growth of new trading centers. The Mongols successfully reduced the cost and danger of overland travel. This made the northern Silk Roads preferable to the southern Indian Ocean routes, which had dominated trade for centuries. Merchants thrived under Mongol rule, enjoying higher status than they had in pre-Mongol China. Although the khanates fought each other, they continued to guarantee the safety of travelers and merchants across their lands, even in times of war.

Genghis and his son, Ögedei Khan, conquered the northern Jin dynasty of China. Genghis’ grandson, Kublai Khan, completed the Mongol conquest of China with his defeat of the Song dynasty in 1279. Control of China made the Mongol khans the rulers of the most important centers of manufacturing in the world. The result was an expansion of the networks connecting the eastern and western halves of Eurasia and an increase in the amount of goods that traveled east to west. But merchants carried more than silk and spice. New ideas traveled across the Silk Roads in the thirteenth and fourteenth centuries. Islamic knowledge of mathematics and medicine made its way to Europe during this period. The Italian city-states adopted the Arabic numbering system. The Mongol khans were generally very tolerant of foreign religions. They offered respect and tax benefits to the leaders of some religions, and people were allowed to worship as they pleased, for the most part. Under Mongol rule, Eurasia became a religious melting pot.

Merchants and priests weren’t the only people who moved. Mongol administration relied on a network of experts and specialists from across Eurasia. When Ögedei Khan decided to build a new capital at Karakorum, he imported thousands of specialists, including artisans and architects. Muslims in particular enjoyed high status in Mongol China. Unable to rely on Chinese bureaucrats, the Khans brought in experts from the Muslim world. They contracted Chinese tax collection to Muslim foreigners.

The Mongols quickly adopted the customs and technologies of conquered peoples. If a foe used superior military technology, the Mongols adopted it. The same was true of science and medicine, which made advances under Mongol rule. Foreign scholars and physicians attained positions of power in the Mongol court. For example, consider astronomers: the Mongols’ religion worshiped a sky god, and they believed their shamans could predict the future by reading the heavens (which they called Tengri). During his invasions, Genghis took foreign astronomers into his service. Later Mongol rulers in China and Persia employed Muslim and Chinese astronomers. These astronomers built scientific networks, and the Khans sponsored new observatories. Astronomers from across the empire flocked to Kublai Khan’s court. These astronomers, like the Persian Jamal al-Din, served as valued advisers on military and political matters, but they also advanced the science of astronomy by exchanging information between the Chinese and Muslim schools.

Experts were central to the Mongol strategy of rule, but not all of them moved willingly. After a conquest, Mongol rulers frequently captured experts and claimed them as personal property. Many thousands were forced to move far from home, accompanying the Khans back to their capitals.

The verdict of history

So, were the Mongols good or bad? As with most historical topics, the answer depends on your perspective. Their conquests were brutal. Millions died in their invasions. Mongol armies sacked entire cities and centers of learning. If you were one of the many abducted experts or others enslaved by the Mongol khans, the Mongol conquests were certainly a bad thing. On the other hand, 800 years later, we can look back and appreciate the many remarkable aspects of Mongol rule. This century-long period of peace—sometimes called the Pax Mongolica—changed the world. New ideas and new goods traveled unimpeded across the largest landmass on Earth. The connections between the east and west ends of Afro-Eurasia had never been closer, and they would not be again until several centuries after the Mongol collapse. These connections brought Western Europe some important benefits—and they escaped the Mongol invasions. An increase in overland trade heightened European access to and desire for luxury goods from the east. Along with this trade came new technologies and navigational techniques that would eventually allow Europeans to build overseas empires. Some historians even suggest that the Mongol invasions might have introduced gunpowder weaponry to Europe.

However, along with these new connections came disease. The expansion of trade under Mongol rule unintentionally allowed the Black Death to spread rapidly across Afro-Eurasia. In Europe, the plague killed as many as 50 million people. The turmoil of the Black Death combined with civil war to weaken the Mongol khanates. In 1368, the Mongol Yuan dynasty fell to the Chinese Ming dynasty. The other khanates began their decline and were gradually replaced by various successor states.

1 In English, alternative spellings of the name Ghengis include Chinggis, Chingis, Jenghiz, and Jinghis. “Khan” is a title meaning “ruler.”