In the early 13th century, Wanyan Yongji, mighty emperor of the Jin, sent a message to an upstart warlord who had had the temerity to invade his territory. “Our empire is as vast as the sea,” it read. “Yours is but a handful of sand. How can we fear you?”


It was a bold statement, but one that was, on the face of it at least, fully justified. For the Jin dynasty of northern China was perhaps the most powerful polity on the face of the Earth at the time. The Jin had unimaginable wealth, gunpowder and an enormous army equipped with state-of-the-art weaponry, such as catapults. What’s more, they could call upon the protection of one of the foremost engineering feats of all time, the Great Wall of China. So why should they be concerned about a nomad army riding roughshod over their land? But there were a couple of problems.

The Jin weren’t facing any old bunch of nomads, and the man commanding them wasn’t any old leader. He was Genghis Khan. Over the next two decades, the Mongol ruler would forge a reputation as arguably the greatest military commander in history. And it was at the very heart of Wanyan Yongji’s empire – in the streets of his magnificent capital, Beijing – that he would announce himself to the world.

By the time his Mongol army first attacked Beijing in 1214, tens of thousands of hapless Chinese men, women and children had already become acquainted with Genghis Khan’s ‘talents’ as a brutal, destructive force. A few years earlier, he had launched a massive invasion of northwest China, pillaging, plundering and killing on an epic scale. Not even the Great Wall could stop him. Instead of attempting to assault it, he simply took his army around the side.

Building an empire

Now, having arrived at Beijing, Genghis Khan faced another wall, the one surrounding the city. It was 12 metres high, 10 miles long and bristling with defenders ready to rain down molten metals, crude oil, even excrement and poisons onto the Mongols. “I had trained my men to attack with the speed of the wind,” Genghis Khan recalled. “Now they had to learn the guile of the wolf.”

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And so he waited… and waited, slowly strangling the Jin capital in a long siege. Thousands starved within the walls and the population resorted to cannibalism. And still Genghis Khan waited until, in early summer 1215, with the populace at breaking point, he ordered his men to storm the city.

Genghis Khan – the butt of a Chinese emperor’s jokes and leader of two million illiterate nomads – brought the Jin to their knees

The walls were scaled, the defenders overcome, and what followed was utter annihilation. For one month, his army burned, plundered and raped with abandon. The city of the utmost sophistication, famed for its grand palaces and markets overflowing with silks and spices, had been reduced to a charnel house. A year later, visiting ambassadors reported that the streets of Beijing were “slippery with human fat”. They also recorded that beyond the walls stood a mountain of bones.

Genghis Khan – the butt of a Chinese emperor’s jokes and leader of two million illiterate nomads – had brought the Jin to their knees. That achievement in itself would have been enough to elevate him into the pantheon of great military commanders. But for Genghis Khan, it was just the start.

Over the course of the century, he and his successors built the largest contiguous empire in the history of the world, a 12-million-square-mile swathe of land that stretched from the Sea of Japan to the grasslands of Hungary in the heart of Europe. To put that into context, the Mongol Empire grew to four times the size of the one created by that other great conqueror, Alexander the Great, and twice the size of the Roman Empire. Some three billion of the seven billion people alive today live in countries that formed part of the Mongol Empire.

Yet perhaps more astonishing still is the story of the catalyst behind this extraordinary feat of empire-building.

Unlike Alexander the Great or Julius Caesar before him, Genghis Khan didn’t fine-tune an already impressive military machine. He turned a rag-bag collection of tribes – with no permanent homes, precious few possessions and a long history of butchering one another – into an unstoppable juggernaut. And he did so from fraught beginnings.

Genghis Khan's rise to power

Genghis Khan didn’t become Genghis Khan until well into his 40s. When he was born in c1162, the son of a tribal warrior chief, he was named Temujin. The Secret History of the Mongols, the oldest-surviving literary work in the Mongolian language, set down shortly after his death, tells us that he was born clutching a blood clot, a sign that he would be a brave warrior.

If Temujin was destined for greatness, there were few signs during his early years. At the age of eight or nine, his father was poisoned by a rival tribe, the Tatars, and he and his mother were rejected by their clan and forced out onto the grasslands of Mongolia, where they survived by foraging for berries, rats and birds. It was a humiliating, pitiful existence. “They left us with nothing,” remembered Temujin. “We had no friends but our own shadows.”

Being friendless in the cut-throat world of 13th-century Mongolia was not a good place to be. The young Temujin came to the realisation that his best chance of reversing his fortunes – and creating a powerbase for himself – lay in establishing alliances.

When he was just 16, he did exactly that by marrying a girl called Börte of the Olkhonud tribe. “Börte was mine and so was her tribe,” was Temujin’s triumphant, if far from romantic, verdict on the union. Yet on the violent, febrile Mongolian steppe, even getting married could spell trouble. No sooner had Temujin and Börte been wed than a rival tribe, the Merkit, ambushed Temujin and rode off with his bride.

Genghis Khan, seated with his wife Börte
Genghis Khan seen seated with his wife Börte; together, they had nine children. (Photo by Getty Images)

Ruler of the Mongols

Temujin was desperate to get revenge, but knew he couldn’t do so on his own. “A man who seeks power needs friends with power,” he would later write. So he sought to secure another alliance, this time with a formidable leader named Toghrul. Temujin won over Toghrul by reminding him that he had fought alongside his father, and sugar-coated the offer with a lavish sable coat. The gambit worked. With the aid of Toghrul’s fighters, Temujin attacked the Merkit and won back his wife. “We destroyed their families and emptied their breasts,” he said. By putting a powerful tribe to sword, Temujin’s ascent to becoming the ultimate power in Mongolia had well and truly begun.

Someone, however, stood in his way, and it was one of his greatest friends. Temujin had been blood brothers with a fellow warrior named Jamukha, also the son of a Mongolian tribal leader, for a number of years. In fact, Jamukha had played an instrumental role in the defeat of the Merkit. Yet, as the two had grown older, cracks began to appear in their friendship. Jamukha had grown distrustful of Temujin’s growing power – especially his penchant for meritocracy, promoting people on the basis of their talent rather than their breeding. Soon, his distrust morphed into outright war.

When Jamukha struck, it was with bloodthirsty ferocity. He defeated Temujin’s fighters high on the plateau of central Mongolia, and then had Temujin’s captured generals boiled alive. “The earth was soaked with the blood of my warriors,” wrote Temujin. “Never again would I be defeated and my loyal warriors so dishonoured.”

He was good to his word, and when his revenge came, it was total. Temujin’s army fell on Jamukha’s warriors in the summer of 1204, defeating them in a blizzard of arrows and cavalry charges. Then a few months later, Jamukha was captured. Rather than dish out a fate similar to what befell his generals, though, Temujin showed him mercy… up to a point. Jamukha asked for a noble death, which meant without the shedding of blood. His former friend granted him that, so had his back broken.

Genghis Khan relied heavily on spies and was certainly not above using fake news as a tactic

Temujin’s victory helped make him the most powerful warrior on the Mongolian steppe. Two years later, he achieved something yet more remarkable, uniting Mongolia’s warring tribes under one leader. Now he would go about turning them into a dynasty defeating fighting force, and he would do so under a new epithet: Genghis Khan, meaning ‘universal ruler’.

Among the first people to feel the force of the newly united Mongol nation was the Western Xia of northwest China, who succumbed to a sustained Mongol invasion. In 1211, Genghis followed that by attacking the Jin, gobbling up land, cities and loot in a spectacular campaign that culminated in the fall of Beijing.

Why were the Mongols so successful?

What, other than Genghis Khan’s military genius, made the Mongols so intimidating? At the heart of their success were their horse-mounted archers who, in the words of historian Frank McLynn, inspired “a quantum leap in military technology”. Mongolians trained in archery and horsemanship from a young age – Genghis Khan probably learned how to fire an arrow from horseback by the age of about three – and mastered how to achieve maximum accuracy by releasing their arrows just as all of their horse’s hooves left the ground.

Mongol archers
Mongol archers during Genghis Khan’s destruction of the west. (Photo by Getty Images)

The Mongolians were highly adept at communicating over large distances, something they had honed over centuries of rounding up animals on the steppe. This enabled them to slowly tighten the noose around the enemy.

Guile was another key weapon in the Mongol armoury. Genghis Khan relied heavily on spies and was certainly not above using fake news as a tactic. In one instance, he employed a campaign of disinformation to confirm one Muslim shah’s suspicion that his subordinates were plotting against him. Genghis Khan was also a master of the feigned retreat, luring opponents out of defensive positions before delivering a lethal strike.

Genghis Khan was, it appears, entirely unrepentant for violence

Combine all this with his ability to quickly assimilate new technologies into his own army – such as Chinese siege weapons, mortars, gunpowder, not to mention thousands of captured troops – and you had a truly formidable foe.

And then, of course, there was terror. “Those who surrendered would be spared,” Genghis Khan is reported as saying. “Those who did not surrender but opposed with struggle and dissension would be annihilated.” It was no idle boast. Cities that put up a fight were routinely subjected to an orgy of destruction: their men butchered, women raped and buildings razed. As a strategy of war, the ‘exemplary massacre’ was utterly brutal, but as a means of dissuading resistance, it was chillingly effective. As many as 30 million people may have died during the Mongols’ campaigns in China alone. Yet in terms of sheer barbarity, the worst was yet to come.

Having subdued the Western Xia and Jin to the east, Genghis Khan looked to establish trade links to his west. He sent emissaries into the Khwarezmid Empire (modern-day Afghanistan and Iraq). They carried – according to contemporary Persian historian Juzjani – the following message to their ruler, Ala ad-Din Muhammad: “I am master of the lands of the rising sun while you rule those of the setting sun. Let us conclude a firm treaty of friendship and peace.” The response was emphatic. It was the head of one of Genghis Khan’s ambassadors in a sack. When he learned of this grisly snub, he flew into a rage that would change the course of history. Within a matter of months, Genghis Khan had dispatched an army of 200,000 men to teach the shah a lesson that the people of central Asia wouldn’t forget for generations.

Some of the most notorious of all Mongol atrocities were perpetrated during this campaign, visited upon the eastern outposts of Islam. The city of Gurganj in modern-day Turkmenistan felt the full brunt of Genghis Khan’s fury. Muslim historians record that, after it succumbed to a five-month siege, 50,000 Mongol soldiers slaughtered ten men each.

Among their other victims was the oasis city of Merv (also Turkmenistan), whose libraries, constituting the greatest collection in central Asia, contained 150,000 volumes. By the time Genghis Khan’s forces had finished, the city and its libraries lay in ruins, and each soldier in the 7,000-strong invading army was allotted around 300 people to kill. Most had their throats slit.

Was Genghis Khan a vengeful tyrant or an enlightened ruler?

The Genghis Khan of popular imagination tends to be a pitiless killer, leading a merciless army across the land and building an empire on the bones of millions. But there was another, often overlooked, side to him, and that was as the enlightened ruler who realised that if his Mongol Empire was to prove sustainable, he would have to work with the peoples he had subjugated.

He certainly wasn’t averse to exploiting these people’s skills, identifying the best artisans across the empire and bringing them back to Mongolia. As a result, his capital of Karakorum bristled with small communities of foreign silversmiths, silk-weavers, artists, architects and the like. And whether they were Christian, Muslim or Buddhist, it appears they were free to worship in peace.

Another key to Genghis Khan’s success was his promotion of trade. The empire made the world a smaller place, in effect serving as a transmission belt for technology, science and goods between areas as diverse as China, Iran and eastern Europe. Without these Mongol trade routes, Marco Polo could never have made his celebrated journey from Europe to China in the late 13th century.

Greasing the wheels of this connectivity was the Mongols’ celebrated postal system. The widereaching network of routes connected by regular staging posts enabled a message to travel 125 miles in a single day. It remained the fastest way of sending messages across Asia until the advent of the railways.

Genghis Khan was, it appears, entirely unrepentant for violence. “I am the punishment of God,” was his defiant message. “If you had not committed great sins, God would not have inflicted a punishment such as me upon you.”

By 1225, the Mongol campaign in central Asia was effectively over. Countless cities had been razed, millions lay dead and Genghis Khan now presided over an empire that extended west to the Caspian Sea.

Was he now prepared to rest on his laurels? To sit back and savour the spoils of victory? Not a bit of it. Mongol texts tells us that Genghis Khan genuinely believed that it was his destiny to conquer the world for his god, Tengri.

Whatever his motivation, within a year he was on the campaign trail again, leading an army back into China. But it was not to be. During 1227, he was taken ill and died only days later. His body was transported all the way back to Mongolia, where it was buried somewhere unknown near a sacred mountain. Its location remains a mystery to this day.

According to legend, Genghis Khan’s last words to a few faithful followers were: “I have conquered for you a large empire. But my life was too short to take the whole world. That I leave to you.” Whether he uttered these short sentences or not, his successors were more than happy to take up the challenge. Genghis Khan was dead, but as the people of Asia and Europe would learn to their cost over the next seven decades, the Mongols weren’t done with conquest quite yet.

Mongols in Europe

Genghis Khan may have breathed his last in 1227, but his death didn’t signal the peak of the Mongol Empire, or the end of their thirst for conquest. Far from it. Genghis Khan’s son and successor, Ögodei Khan, had a lust for land and spoil every bit as insatiable as his father, and the people of eastern Europe would soon reap the consequences.

In the autumn of 1237, a Mongol army crossed the Middle Volga and fell upon the principalities of central Russia. Town after town was ransacked, including, in 1240, Kiev. “After they had besieged the city for a long time,” reported the papal envoy Giovanni da Pian del Carpini, “they took it and put the inhabitants to death.”

Then the Mongols surged into Poland and Hungary, the speed of their cavalry, the firing range of their archers and their well-honed siege methods overwhelming the defenders. By 1241, as shock troops raided the outskirts of Vienna, western Europe appeared to be at the mercy of the Mongols. But then, virtually overnight, they were gone. Ögodei had died suddenly and his armies had returned home to elect a new khan, never to return. Europe had got a spectacular break.


What is Genghis Khan's legacy?

John Man, author of 'The Mongol Empire: Genghis Khan, His Heirs and the Founding of Modern China' (Corgi, 2015), answers some of the biggest questions surrounding the Mongol warlord

What made Genghis Khan a great leader?

He never stopped learning and was endlessly willing to adapt. He realised early on that the only way to prosper was to strike alliances with rival tribes. Then, when he became Genghis Khan, he came up with the idea of breaking up tribes and distributing them into different parts of the army. This was a brilliant way of quelling inter-tribal feuding. And, of course, he promoted through merit, which meant that the greatest talents got to the top.

Is Genghis Khan the world's greatest military commander?

He’s undoubtedly in the top three. You could make an argument for Alexander the Great rivalling him. The same goes for Napoleon who, like Genghis Khan, was a genius at marshalling both the military and civil side of his administration.

How did he ensure loyalty among his followers?

Everyone loves a winner. The more he won, the more people rallied to his flag. And in a country without money, many would have been attracted by the spoils of war. Genghis Khan was generous to those who showed loyalty – he was not the sort of leader to squirrel his wealth away in the 13th-century equivalent of a Swiss bank account!

How bloodthristy was Genghis Khan?

A: He was more bloodthirsty than his contemporaries, but that’s only because he was more successful. I’d argue that he showed great restraint. He realised that to create an empire, he had to work with people afterwards, and would only resort to killing if it served his purpose. That probably explains his use of the ‘exemplary massacre’. Sieges are extremely expensive and require a lot of manpower – the best way to avoid them was to terrify cities into surrendering in advance.

What was Genghis Khan's greatest military victory?

The siege of Beijing. It was the first really big one. Once he had captured one major city, he acquired more manpower and siege weapons to use against others.

What motivated Genghis Khan's conquests?

According to later Mongolian sources, he was inspired by the heavens to rule the Earth. I think that idea came from hindsight, not the man himself. I’d argue that each conquest inspired the next, until the whole thing gathered an unstoppable momentum. Empires are never big enough or secure enough – if you’re the emperor, you’ve always got to keep going.

 Did Genghis Khan change the world?

His greatest legacy was, for me, the vision of world rule that grew up after his death – put into practice by his son Ögodei and grandson Kublai Khan. That ultimately led to the unification of China, and it’s remained unified ever since. So it could be argued that perhaps his longest-lasting achievement is modern-day China.

This article was first published in the November 2018 issue of BBC History Revealed magazine


Spencer MizenSenior Production Editor, BBC History Magazine

Spencer is senior production editor of BBC History Magazine