The Advance of the Mongols: 6 Campaigns That Built the World’s Largest Land Empire

The Advance of the Mongols: 6 Campaigns That Built the World’s Largest Land Empire

Kurt Christopher - July 13, 2017

At the end of the twelfth century the Mongols were a tribal people. They led a nomadic life centered on their horses. They moved with the horses to find pasture that had not yet been exhausted, supporting themselves on the horses’ milk and blood. Unsurprisingly, they were fantastic horsemen and archers, frequently supplementing their pastoral livelihood with raids on the trade routes that linked China, India, and Persia.

Early in the thirteenth century a single Mongol chieftain by the name Temujin would unite the eastern Mongolian tribes into a confederation. Having united the tribes Temujin took on the name “Universal Leader” or Genghis Khan. In the course of a generation he would transform the Mongol tribes from a minor nuisance to caravans into the most fearsome army the world had ever seen. What follows are the most significant campaigns in the creation of the largest land empire in history.

The Advance of the Mongols: 6 Campaigns That Built the World’s Largest Land Empire
Genghis Kahn. National Palace Museum

The Conquest of Western Xia and Jin China

In 1207, the year after taking his title, Genghis Khan embarked upon his first expansionist project. He cast his eye upon the Chinese Western Xia dynasty. His people were not yet strong enough to challenge the Western Xia directly, so they first fortified themselves by raiding the borderlands and harassing garrisons. By 1209 Genghis Khan was confident enough to commit his followers to a full scale invasion. When the Western Xia Emperor Li Anquan received news that the Mogols were advancing up the Yellow River towards the capital at Yinchuan he appealed to the Emperor of Jin China for help, but none came.

In the ensuing invasion the Mongols would demonstrate that while they were virtually invulnerable in the open field, they were still amateurs when it came to siege warfare. At Kiemen they attempted for two months to take a fortress on the Yellow River but proved incapable of subduing a fortified position. The deadlock between the two parties was only broken when Ghenghis Khan bluffed a retreat to draw the defenders out of the fortress and onto clear ground where the Mongols could take advantage of their quick horses archers to annihilate the garrison.

Having cleared out Kiemen, the Mongols followed the river to Yinchuan, seeking Li Anquan’s submission. The Emperor, still in control of twice as many men as the Khan, chose to defend his city. With their difficulties at Kiemen still fresh in mind, the Mongols chose a different approach to this new fortress. They molded the earth near the Yellow River to build a channel that would redirect the river into the city, hoping to flood the defenders out. The dykes that they built for the project were faulty, though, and when they released the river one of them gave out and flooded the Mongol camp.

Though their plan to drown Yinchuan had failed, damage to the irrigation infrastructure from the river diversion and Mongol pillaging had ravaged crops in the area. Faced with an impeding famine, Li Anquan gave in and pledged his support to the Mongols. In what would become a hallmark of his approach to conquered people under his rule, Genghis Khan granted Li Anquan mercy in exchange for his support in future campaigns.

In 1211 Genghis Khan would make the Jin Emperor regret his decision not to aid the Western Xia dynasty when his lands became the next target of the Mongols. Just as before, the Mongols were simply unbeatable in the field but would struggle with city sieges. But with the help of their new Chinese vassals they were able to construct catapults and subdue all the cities between the Yellow River and the Great Wall. The capital at Yanjing, now called Beijing, fell in 1215 making the Mongols the masters of northern China.

The Advance of the Mongols: 6 Campaigns That Built the World’s Largest Land Empire
Illustration of a Mongol facing off against a Khwarezmid. Pinterest

The Invasion of the Khwarazmid Empire

To the west of the Mongol heartland lay the Khwarezmid Empire, an Islamic Empire ruled by Shah Ala ad-Din Muhammad. The Sultan was well aware of the recent increase in Mongol wealth and stature, but at the time he was more concerned with his ongoing political contest with the Caliph in Baghdad who held claim to the allegiance of all Muslims. So when the Mongols, flush with the riches of China, approached the Shah with a proposal to open a trade between them he agreed.

When the first Mongol caravan arrived in the city of Otrar, however, the governor there accused them of being spies and arrested them. Mongol emissaries soon appeared, demanding the release of the caravan, but the governor cut the head off of one of them in response. Unwilling to accept this affront, Genghis Khan dispatched an army of more than 100,000 men into Persia in 1219 to get his revenge upon the Khwarezmian Shah. He tasked one contingent of this army with a single mission: to hunt down and kill Shah Ala ad-Din Muhammad.

Still, the main force remained under the direct command of the Khan. It proceeded to Otra and invested the city for five months before taking the walls. The governor, who had himself precipitated the invasion when he executed a Mongol emissary, held out in the citadel for another month. When the Mongols finally broke into the fortress he retreated with his men up the citadel, floor by floor, eventually crawling out onto the roof and throwing tiles down on the invaders when all other options evaporated. He was captured all the same, and Genghis Khan had him executed.

From Otra the Mongols went on to take Bukhara and then the Khwarezmian capital at Samarkand. The Shah fled while the Mongols led the population out of the city for execution. Their heads were stacked into pyramids. Though the Shah would succumb to sickness soon thereafter, Genghis Khan pushed ahead. What followed was a campaign of annihilation in which the entire population of one city after another was put to the sword. As many as 1,200,000 may have died in Urgench, and the Mongols killed another 700,000 at Merv. At Nishapur they even killed the cats and the dogs in the streets so that nothing would be left alive.

The Advance of the Mongols: 6 Campaigns That Built the World’s Largest Land Empire
A contemporary illustration of the Mongol attack on the Assassin fortress of Alamut. Stanford

The Destruction of the Assassins

After the death of Ogedei in 1241 the Mongols experienced a decade of infighting before a new leader, Mongke Khan, came to power. After stabilizing his empire following this period of disunity Mongke Khan looked to the west. A Caliph sat in Baghdad who possessed a competing claim to the loyalty of the Muslims in the Mongol Empire. Mongke charged his brother, Hulegu, with driving through the Middle East as far as Egypt in order to suppress this threat. Before they could challenge the Caliph, though, they would have to contend with an organization of Shia Muslims in Persia, the Assassins.

The Assassins maintained a network of fortifications in northern and eastern Persia, the most impressive of these being the castle at Alamut. They had become notorious for murdering prominent personalities who opposed their Isma’ili beliefs, so notorious in fact that they their name, Assassin, became synonymous with killer. When the Mongols began to press in on the region controlled by the Assassins they hatched a plot to send 400 men with daggers to murder Mongke Khan. The plot was betrayed, though, and Hulegu would bring his army to exact punishment.

In early 1256 Hulegu and his army crossed the Oxus river and into Persia with siege engineers, catapults, and Chinese gunpowder in tow. They made for the castle at Alamut, intent on striking the head off of the Assassin snake by taking the order’s leader Ruhk ad-Din. Still the castle, on top of a six thousand foot mountain near the Caspian Sea and surrounded by sheer cliffs, was considered by most to be impregnable. Undeterred, the Mongols dragged their catapults, along with large boulders to use as ammunition, up the mountainside. Ruhk ad-Din surrendered Alamut shortly after the catapults began to bring its walls down.

Having taken the Assassin bastion the Mongols proceeded to kill all of its inhabitants down to the women and children. They spared Ruhk ad-Din though, taking him prisoner. For the next two years the Mongols brought Ruhk ad-Din along as they subdued one Assassin fortress after another. As they approached each fortress the Mongols would trot out Ruhk ad-Din, demonstrating that they had already taken the leader of the entire order, and demand surrender. Some of the Assassin strongpoints gave in, others fought, but all eventually met the same fate as Alamut: annihilation.’

The Advance of the Mongols: 6 Campaigns That Built the World’s Largest Land Empire
A depiction of the Mongol siege of Baghdad.

The Razing of Baghdad

In 1258, with the Assassins dispatched, Hulegu turned his attention towards his main objective: Baghdad and the Abbasid Caliph Al-Musta’sim. As word of the demise of the Assassins spread local warlords prostrated themselves before Hulegu and offered him their soldiers, doubling the size of the Mongol force. Newly reinforced, Hulegu sent a messenger to Al-Musta’sim demanding that he surrender. The Caliph was persuaded by his chief minister, Al-Alkami, to refuse Hulegu’s demand. What he did not know was that Al-Alkami, was intentionally misleading him. Al-Alkami had been spying for the Mongols and expected that if Baghdad were to fall he might benefit personally.

Al-Musta’sim remained confident, not realizing that he would actually have to defend the city until the Mongols drew to within a day’s ride of Baghdad. He called on the city’s garrison of 20,000 men to ride out and challenge Hulegu, but when the garrison encamped near the Tigris River the Mongols pulled down nearby dykes and dams on the river and flooded the garrison’s camp. Those who did not drown were ridden down by the Mongol’s heavy cavalry.

While the core of Baghdad’s defense already eliminated, Hulegu’s forces went to work on the city itself. The surrounded the city, digging a trench and building a palisade to prevent any of the inhabitants from escaping. Then the bombardment began. Because the Mongols had reached the city faster than they expected the carts carrying the ammunition for the catapults, in disrepair after being dragged up and down the mountains to fight the Assassins, had not yet arrived. They improvised by launching stumps of palm trees and the foundations of buildings into Baghdad. This rain of odds and end continued for a week before the Mongols finally stormed the ninety foot high eastern wall.

When the Mongols breached the walls Al-Musta’sim attempted to open negotiations with Hulegu, but it was too late. The city surrendered, and the Mongols led what remained of the Baghdad garrison out and executed them one by one. The Caliph exited the city last. After a few taunts from Hulegu was rolled up in a rug and trampled to death by horses, an execution method that complied with the Mongol belief that no man can kill a king and that no royal blood should touch the ground.

Following the death of the Caliph the Mongols moved in to sack Baghdad. The population, which estimates put at 800,000 to 2,000,000 people, was massacred. A few Christians and Jews with connections to Hulegu’s allies were spared, and some of the women and children were kept as slaves, but the rest would die. The city burned, and the Tigris ran black with the ink of the books cast into it from the “House of Wisdom,” the product of four hundred years of work collecting and translating all the knowledge of the known world. Baghdad would never full recover.

The Advance of the Mongols: 6 Campaigns That Built the World’s Largest Land Empire
Mamluk warriors at the Battle of Ayn Jalut. Pinterest

The Battle of Ayn Jalut

After destroying Baghdad Hulegu hunkered down for a time, collecting his spoils and receiving new offers of submission and troops from the surrounding region. Once again reinforced, he set out in 1259 to complete the task that his brother Mongke had given him by pushing to Egypt. They crossed the Euphrates on a pontoon bridge and made for Aleppo. While Aleppo fell quickly the soldiers in the central citadel continued to defend their last refuge for four weeks before surrendering. In a show of respect for their courage Hulegu allowed the survivors of the citadel to live.

From Aleppo the Mongols advanced to Damascus, which gave in without a fight. Now only the only significant authority capable of challenging the Mongols remaining in the region were the Mamluks of Egypt. Hulegu sent an emissary to Sultan Qutuz carrying a message that read, “You have heard that we have conquered a vast empire and have purified the earth of the disorders that tainted it. It is for you to fly and for us to pursue…. We mean well by our warning, for now you are the only enemy against whom we have to march.”

The Mamluks, descendants of slave soldiers who had unseated their masters, were not interested in being enslaved once again. They responded to Hulegu’s threat by killing the emissary. With this action Qutuz could expect to face the Mongols’ full wrath, but then fate intervened. As Hulegu was preparing his advance towards Egypt a rider arrived with news from China: Mongke Khan had died of dysentery. Fearing that the Khan’s death might destabilize the empire Hulegu withdrew along with a considerable portion of his force, leaving his lieutenant Kitbuga to chastise the Mamluks.

Back in Cairo Qutuz had decided that his capital could not endure a Mongol siege, and that his best chance for success was to meet the Mongols in the open. The Mamluks crossed Gaza and positioned themselves to intercept the Mongols in Galilee at a place called Ayn Jalut, which quite appropriately is also the site where David is said to have slain Goliath. Upon arriving Qutuz hid a portion of his army in the highlands nearby to surprise the Mongols if given a chance.

Once the battle began the Mamluks were able to lure the Mongol force into this trap by repeatedly hitting them and then withdrawing closer to the highlands. The unexpected appearance of Mamluk archers and cavalry from the hills overwhelmed the Mongols, surrounding them. Not easily discouraged, the Mongols fought fiercely to break out of the encirclement, prompting Qutuz to personally join the battle to try and prevent a breach. Despite Qutuz’s efforts some of the Mongols did manage to escape and regroup, but he held the battlefield. The Mamluk’s had done what no other power had been capable of – they had stood up to a Mongol advance and won.

The Advance of the Mongols: 6 Campaigns That Built the World’s Largest Land Empire
Depiction of Mongol soldiers facing Song Chinese rockets. Quora

The Subjugation of Song China

While Mongols were engaged in subduing the Jin Chinese they had maintained an alliance with the Song Dynasty in southern China, but a territory dispute between the two over the spoils of the defeated Jin precipitated a war between the former allies in 1235. Unlike previous Mongol campaigns, the Song Chinese would prove resilient and hold out against the Mongols for over forty years. For sixteen years the Mongols struggled just to get a handhold in the Song territories near Chengdu. When Mongke Khan came to power in 1251 he would reenergize the Mongol efforts to master the Song dynasty.

While Mongke Khan had charged his brother Hulegu with incorporating the Middle East into the empire, for Mongke that was more of a side show. China was far more important to Mongke, so much so that he would personally lead the campaign there along with his brother Kublai. Together the brothers would take Tibet and the Kingdom of Dali, but the Mongols would suffer a disaster in 1259 when Mongke succumbed to an illness during a failed attack on the Diaoyu Fortress in Sichuan.

Kublai would take up the position of Khan after Mongke’s death, committed to pursuing the campaign against the Song to its conclusion. He found an unlikely ally in the general leading the Diaoyu Fortress that had just defeated Mongke. Unhappy with the Song dynasty’s chilly reaction to his defense against the Mongols, this general defected to Kublai and guided them to the Song weak point at Xiangyang. Kublai heeded this advice and, with the help of some Arab siege engineers imported from Hulegu’s conquests, captured the city.

The siege of Xiangyang had been a long ordeal for the Mongols, the city had managed to hold out for years. But it was even more exhausting for the Song Chinese. One attempt to relieve the city after another had been massacred by the Mongols. After Xiangyang fell the Song would commit to one final decisive battle at Yuhue, but their forces had been so seriously depleted at Xiangyang that they no longer had the ability to put together real resistance. In 1276 the Song dynasty capitulated to the Mongols, and Kublai Khan took on the title of Emperor of China.