The Mongol Empire: The Most Terrifying Land Empire in History

It is the 1200s. You live in a city. Markets. Mosques. Libraries. Thousands of people going about their day. Then one morning, hundreds of thousands riders appear. Their message is simple. Surrender or die. That was the choice facing dozens of cities across Asia and the Middle East during this period. The people delivering that choice were nomads. People who, just a generation earlier, lived in felt tents and herded sheep across one of the harshest stretches of land on Earth. I am talking about the Mongols. This is the story of the Mongol Empire. Before we get to the conquests, we need to understand where this all started. The Mongol Empire did not rise from some wealthy, sophisticated civilization with long-standing institutions and professional armies. It rose from one of the most unforgiving places on Earth. The Mongolian Steppe. A vast stretch of open grassland rolling across Central Asia. Bigger than Western Europe, mostly empty, and brutal in every season. Summers could be searingly hot. Winters were some of the coldest temperatures inhabited land on Earth regularly experienced. Food was not guaranteed. Nothing was guaranteed. Yet the people who lived there were incredibly adapted to this environment. The Mongols and the other nomadic tribes of the steppe were pastoralists. They herded sheep, goats, horses, camels. They moved with the seasons, following the grass. Their homes were yurts. Circular felt tents that could be assembled and dismantled in under an hour. Loaded onto wagons and carried across the steppe. Their diet was built around what the animals gave them. Milk, cheese, yogurt, dried curds, and kumis. A mildly alcoholic drink fermented from mare's milk that was consumed constantly and in large quantities. Let's talk about horses. Everything was about horses. Mongol children learned to ride before they fully learned to walk. Archery was not a skill you practiced. It was something you did from the saddle, at speed, from childhood. The Mongols held a seasonal hunting event called the Nurge, where hundreds of riders would spread out across a vast stretch of steppe, form a circle, and slowly drive every animal in that circle, deer, wolves, foxes, whatever, into a smaller and smaller space until the hunters could take them easily. This was not just about food. This was military training disguised as hunting. The coordination, the communication over huge distances, the discipline of holding the line, all of it transferred directly to warfare. But there was a problem with the steppe in the 1100s. It was not one people. It was dozens of competing clans and tribal confederations. Mongols, Tatarud, Mergid, Naiman, Herayd, and they were constantly at war with each other. Raiding, kidnapping, revenge cycles that stretched back generations. There was no law beyond what your clan could enforce. No overarching authority. Just an endless grinding conflict between groups that were more alike than different. Into this world, sometime around 1162, a boy was born who would end all of that. His birth name was Temujin. He was born near the Onon River in what is now northern Mongolia. His father, Esugei, was a minor chieftain of the Borjigin clan. Not powerful, but respected. His mother, Hoylan, had actually been kidnapped by Esugei from another man of the Mergid tribe while she was already a new bride. That kidnapping, a common enough occurrence on the steppe, would have consequences for Temujin's entire life. The oldest Mongolian written record of Genghis Khan's life, The Secret History of the Mongols, written anonymously sometime after his death, says that Temujin was born clutching a blood clot in his right hand. In Mongol culture, this was an omen, a sign that this child was destined to shed blood and to be great. Whether that detail is literal or symbolic, the book records it as truth. Given what followed, it is hard to argue with the symbolism. When Temujin was about nine years old, his father was poisoned. Esugei had stopped to eat with a group of Tatarud, the same group that had long been enemies of the Mongols. They slipped something into his food. He made it part of the way home and died on the steppe. His body was barely cold when the clans that had followed him made their decision. This boy is not old enough to lead us. So they left, every single one of them. Just walked away with their herds and their families and their tents, leaving Hoylan and her children with almost nothing. What followed was years of near poverty. The family survived by foraging wild fruits, roots, mice, marmots. Temujin and his brothers fished in the Onon River. There was a period of genuine starvation. In a fight over food with his older half-brother Begta, Temujin killed him. His mother was furious. But the act told you something about who Temujin was becoming. Someone who would not accept powerlessness. As a young man, he was captured by the Taichi-ud, a rival clan. And enslaved. He wore a kangwe, a kind of portable wooden stock around his neck, used to restrict movement. He escaped at night, hiding in the Onon River, and made it back to his family. That escape built his reputation. Men started to follow him. Around 1178, he married Borte, a girl his father had arranged for him before he died. It was a political alliance, and it mattered. Her family had connections. Through marriage, he was building the beginning of a network. But the Mergid, the tribe his father had once stolen his mother from generations back, had not forgotten. They raided Temujin's camp and took Borte. And this is where the story truly begins. To get Borte back, Temujin needed allies. He went to Togrul Toril Khan, the Wang Khan of the Kerait tribe. A powerful leader who owed Esuhay a favor. He also called on his blood brother, Jamukha, a fellow Mongol chief he had been friends with since childhood. Together, they rode against the Mergid, defeated them, and Borte was freed. She was pregnant when they found her. Temujin accepted the child, Xuchi, as his own. Though the question of whether Xuchi was truly his son would shadow the family for decades, the rescue was more than personal. It was Temujin's first real military operation. It worked. More men began to see him as someone worth following. Through the 1180s and 1190s, Temujin and Jamukha led a joint confederation. They were close blood brothers who had sworn oaths of friendship. But underneath the partnership was a deep ideological difference. Jamukha was a traditionalist. He believed power should flow through noble bloodlines. That the old aristocratic clan system was the right way to organize Mongol society. Temujin believed something different. He thought loyalty and merit should count more than birth. That difference eventually broke them. Jamukha moved against Temujin in around 1187, defeated him badly, and reportedly boiled the commanders of Temujin's captured units alive as a warning. It was a crushing setback. Temujin retreated, rebuilt, spent time as a vassal under the Jin dynasty in China. He was patient. When he re-emerged in strength in the 1190s, he began systematically dismantling every rival confederation. First the Tatarud, the people who had poisoned his father. He defeated them in battle around 1202 and issued an order that has gone down in Mongolian history. Every male Tatar who stood taller than the lynchpin of a wagon wheel was to be executed. The Tatarud, as a people, ceased to exist. The surviving women and children were absorbed into the Mongol confederation. The same pattern followed with other tribes. The Mergid, defeated. The Naiman, defeated. Finally, Toril Khan himself turned against Temujin, launched a surprise attack in 1203, and was defeated and killed. The man who had once helped rescue Borte was now gone too. By 1205, Jamukha, Temujin's oldest friend and greatest rival, had been captured. His own men handed him over. Temujin offered him a position at his side. Jamukha refused. He asked only for a noble death. One without the shedding of blood, as tradition demanded. So his back was broken. He died as he had lived, on his own terms, but defeated. In 1206, on the banks of the Onon River, the chiefs of every major clan on the Mongolian plateau gathered for a great assembly. A Hurrildai, a nine-tailed white standard, the symbol of Mongol sovereignty, was raised. Temujin was proclaimed Chinggis Khan, meaning universal ruler or ocean ruler, ruler of everything in all directions, without limit. The leading shaman, Hohochu, declared that Tengger, the eternal blue sky, the supreme god of the Mongols, had chosen Chinggis Khan to rule the world. The political had become divine. To oppose the Khan was to oppose the will of heaven itself. From this point forward, that was the lens through which every single conquest was framed. Before we get into the campaigns, we need to talk about the tool. The Mongol army was not what most people imagine when they hear the word horde. That word suggests chaos. The Mongol army was the opposite of chaos. The first thing Chinggis Khan did after uniting the tribes in 1206 was reorganize his entire military on the decimal system. Every soldier belonged to a unit of ten, an arvan. Ten arvan made a hundred, a zun. Ten hundreds made a thousand, a mangan. Ten thousands made a two-men. At each level, there was a commander responsible for the performance of his unit. The revolutionary part was not the structure itself. It was what went inside the structure. Chinggis Khan deliberately mixed men from different tribes into the same units. A warrior's old clan meant nothing now. Your unit was your family. Your loyalty was to your arvan commander, and through him to the Khan. Old tribal allegiances, the source of constant steppe warfare, were simply dissolved. Men who had been enemies the year before were now sleeping in the same camp, watching each other's backs. It worked, because the system backed it with merit. Advancement was based on performance, not birth. The best commanders rose regardless of where they came from. The most elite unit was the Hishig-ten, the imperial guard. Ten thousand strong, personally selected, they protected the Khan and served as a training ground for future generals. Many of the greatest Mongol commanders came through the Hishig-ten. The weapon that made all of this devastating was the Mongol composite recurve bow. Made from layers of bone, sinew, and wood, it was shorter than a longbow but far more powerful for its size. And critically, it could be used from horseback. A Mongol warrior could fire at full gallop, draw the bow from about 160 pounds of pull, and hit targets at distances of 300 yards or more. In battle, a unit of Mongol cavalry could shower an enemy with arrows faster than almost anything they had ever seen, while staying far enough back to avoid close combat. Their core battlefield tactic was the feigned retreat. The Tolguma. A Mongol unit would engage the enemy, then appear to break and run. The enemy, thinking they had won, would chase. That is when the real attack came. The fleeing Mongols would wheel, the flanks would close in from the sides, and the pursuing enemy force would find itself surrounded and destroyed. Armies fell for this over and over again, across three continents. Because every instinct told a cavalry commander that a fleeing enemy was a beaten one. Mongol psychology was built to exploit that instinct. The Mongols were astonishing adapters. They had no siege tradition. Nomads do not build fortresses, so they had never needed to take them down. But when they ran into walled cities, they did not give up. They recruited engineers. Chinese engineers taught them catapults and counterweight trebuchets. Persian engineers taught them naphtha fire weapons. Mongol forces would arrive at a city with the engineers to build siege weapons from local materials. They were faster at this than most armies were at deploying pre-built equipment. Their psychological warfare was equally calculated. Before any city, they offered a choice. Surrender now, pay tribute, supply the army, and we move on. Refuse, and we destroy everything. They kept this bargain on both sides. Cities that surrendered were largely spared. Cities that resisted, or worse, that surrendered and then rebelled, were annihilated. Then they let survivors go, not out of mercy. So those survivors would walk to the next city and describe what had happened. Many cities surrendered without a fight. That was the point. Behind all of this was an intelligence apparatus that was decades ahead of its time. Before any major campaign, Mongol spies, disguised as merchants, travelers, or diplomats, had already been through the target territory. They knew the roads, the water sources, the political fractures, the strength of the armies. Chinggis Khan never went into battle uninformed. The army also moved with extraordinary speed. Each warrior had three to five horses. They rotated between them constantly, allowing the army to cover distances that sedentary armies simply could not match. They carried dried meat, pressed into a form called borts, that could be reconstituted with water. No supply train, no wagon camp full of grain. The army was the supply system, and it could move fast. The first target beyond Mongolia was the Xixia, the Tangut Kingdom in northwestern China. The Tanguts had a significant state, controlled important trade routes, and had historically served as a kind of buffer state between the Mongols and the much larger powers to the south. Chinggis Khan tested his army against them starting in 1205, with larger raids in 1207 and 1209, and eventually forced a submission in 1210. The Tanguts became a tributary. They would pay, supply soldiers, and acknowledge Mongol supremacy. For now. Then came the real target. The Jin Dynasty ruled northern China, one of the wealthiest and most populous regions on earth. For years, the Mongols had been on the subordinate end of their relationship with the Jin, paying tribute, performing obeisance. Chinggis Khan had a very clear view of what he wanted to do about that arrangement. In 1211, he crossed the Gobi Desert with a force estimated at somewhere between 65,000 and 100,000 cavalry. The Jin Empire had an army of hundreds of thousands, with fortified cities, walls, professional troops, and the accumulated wealth of generations. None of it was enough. The Mongols destroyed the Jin field armies in a series of devastating engagements, including the massive Battle of Yehuling in 1211. They began systematically working through northern China, not always taking every city immediately, but cutting off supply lines, destroying the agricultural hinterland, stripping the countryside of everything the Jin armies needed to function. By 1215, Zhongdu, modern Beijing, one of the largest and most important cities in the world at the time, fell. The Jin Dynasty was not fully destroyed yet. They moved their capital south and held on, but the north was gone. The Mongols had their foothold in China, and with it, something even more valuable – Chinese engineers and administrators. This was the moment the Mongol military became a true siege force. Chinese engineers showed them how to build counterweight trebuchets and use fire weapons. Persian and Chinese administrators came into Mongol service, teaching them how to tax, govern and extract wealth from sedentary populations on a scale that nomadic raiding could never achieve. While the campaigns in China were still ongoing, Chinggis Khan turned his attention westward. The reason was, in some ways, absurdly simple. The Khawazm Empire controlled much of what is now Iran, Uzbekistan, Turkmenistan and Afghanistan. It was a powerful Islamic state, ruled by Shah Muhammad II and sat astride the Central Asian trade routes, the Silk Road's western arteries. Chinggis Khan had no initial interest in conquering it. He sent a trade caravan of 450 merchants, Muslim merchants, incidentally, because many of the Mongol Khan's close trading partners were Muslim, with a friendly message essentially proposing open trade. The governor of the city of Utra, a man named Ainulchuk, decided the merchants were spies. He had all 450 executed and confiscated their goods. Chinggis Khan, who genuinely wanted trade, not war, sent a formal diplomatic delegation to the Shah, asking for justice and the return of the goods. The Shah had the senior envoy killed and other two were humiliated and sent back. There is really no other way to say this. What followed was one of the most catastrophic military responses in the history of human civilization. In 1219, Chinggis Khan moved west with an army that sources suggest was between 100,000 and 200,000 soldiers. He divided them into multiple columns that struck from different directions simultaneously. The Shah Muhammad II was a powerful ruler, but his forces were scattered, his loyalty networks fractured, and he had no answer for what was coming at him. Utrar fell first. The governor Ainulchuk was captured alive. Chinggis Khan reportedly had molten silver poured into his eyes and ears. Poetic justice in Mongol style. Then came the great cities of Central Asia, some of the most magnificent in the Islamic world. Bukhara, Samarkand, Maru, Nishabur, city after city, taken and destroyed. The Persian historian Atamluk Joini, who actually worked for the Mongols later in his career and had access to their records, wrote about the fall of Maru, one of the great metropolises of the medieval world. He described how scribes were sent to count the dead after the city fell. According to his account, they counted 1.3 million. How that is exact, we cannot know. But even accounting for medieval exaggeration, what happened at Maru was a catastrophe on a scale that modern archaeology still bears out. The city was essentially abandoned for generations. Nishabur, which had briefly risen in revolt after submitting, was given no mercy. Persian chronicles describe the skulls of the dead being arranged into pyramids as a monument and a warning. The great irrigation systems of Central Asia, canals that had watered cities for a thousand years, were destroyed. Some regions simply never recovered to their pre-Mongol population levels. The Shah Muhammad II fled. He was hunted across his own empire by a Mongol force under the generals Zev and Sübe'etei, two of the greatest commanders in Mongol history, and eventually died on a small island in the Caspian Sea, reportedly without even a proper burial shroud to cover him. Zev and Sübe'etei did not stop. They continued west, through Azerbaijan, Georgia, and into the Caucasus. They devastated Georgia's army. They circled the Caspian Sea. They reached the Crimea, defeated a combined Kuman-Rus force at the Battle of the Kalka River in 1223, giving Russia its first taste of Mongol power, and then rode back east to rejoin Chinggis Khan, a reconnaissance mission of 10,000 men that crossed more territory than Alexander the Great ever conquered. A preview, a warning of what was coming. By 1226, Chinggis Khan was old. He was probably somewhere in his mid-60s, though given the uncertainty around his birth year, some historians place him in his early 70s. He was still campaigning. The Xixia, the Tanguts, his very first real conquest, had refused to send troops for the Khwarazm campaign. That refusal was not something Chinggis Khan forgot, or forgave. He launched a final campaign against the Xixia in 1226. During this campaign, he was reportedly injured in a fall from his horse during a hunting expedition. He continued regardless. The Xixia capital was besieged. But Chinggis Khan died before it fell, in August 1227. The Secret History of the Mongols describes his death with four words that feel deliberately vague. He ascended to heaven. His body was carried back to Mongolia. According to tradition, everyone who witnessed the funeral procession was killed, to keep the route and the burial site secret. The escort reportedly slaughtered every person they encountered on the road back. Thousands dead so that no outsider would know where Chinggis Khan rested. To this day, no one knows where he is buried. Archaeological teams have searched for decades. His burial mound has never been found. He wanted it that way. He had instructed that the site be unmarked and secret, so that no enemy could ever desecrate it. Before he died, he had arranged the succession. His third son, Ogedei, would be Great Khan. Not Zhu Qi, whose paternity was always questioned and who had died just months before Genghis anyway. Not Sagadai, too aggressive and difficult. Not Tului, the youngest, who would inherit the Mongolian homeland by tradition. Ogedei, pragmatic, intelligent, charming and capable of holding the family together. The empire was notionally divided among all four sons and their lines. Zhu Qi's territory in the west, later the Golden Horde. Sagadai's Central Asian lands. Ogedei's East Asian and Chinese domains. And Tului's Mongolian heartland. But the Great Khan, whoever held that title, was the supreme authority over all of it. As long as the family agreed on who that was, the empire would hold. Chinggis Khan was gone. The empire he built, in 21 years of near constant war, was the largest the world had ever seen. And it was about to get larger. It took two years after Chinggis Khan's death to convene a proper huraldai and elect Ogedei as Great Khan in 1229. Once he was seated, the campaigns resumed almost immediately. Ogedei was not a warrior in the mold of his father. He was, by the accounts of his own court historians, fond of drink. His brother Sagadai, who was more puritanical, appointed a man specifically to limit the number of cups Ogedei drank per day. Ogedei acknowledged this was probably necessary and then found ways around the limits. He was that kind of man. Smart enough to know his weaknesses, charming enough that people loved him anyway, and wise enough to delegate to people better than himself in areas where he was lacking. Under his reign, the Jin dynasty of China, which had survived Chinggis Khan's campaigns, was finally finished. By 1234, the last Jin emperor was dead and northern China was fully in Mongol hands. Ogedei sent administrators in, began extracting tax revenue, and started building the Mongol capital at Kharkhorum, with palaces and temples and a genuine permanent infrastructure for the first time in Mongol history. He also established the Ur-2, the postal relay system, a network of stations across the empire spaced roughly 20 to 40 miles apart, each stocked with fresh horses, food, and riders. A message could travel thousands of miles in days. A merchant could move goods across the continent with reasonable safety. This was the infrastructure of the Pax Mongolica, the Mongol peace, that would come to define this era. Then the Western campaigns. Ogedei sent his nephew Batu Bat Khan, son of Xuchi, and gave him the greatest general alive, Subedei. They moved into Russia in 1236. Ryazan fell in December 1237. The city asked for help from its neighbors and got none. It was burned to the ground. Vladimir fell. Suzdal fell. By 1240, Kiev, the heart of the Rus' civilization, one of the great cities of Eastern Europe, was reduced to ruins. A Franciscan friar who visited the ruins several years later described bones and skulls scattered across the fields outside the city as far as he could see. In 1241, Bat and Subedei drove into Poland and Hungary simultaneously, with separate armies. At the Battle of Legnica, a combined army of Polish knights and German Teutonic knights was destroyed. At the Battle of Mohi in Hungary, King Bela IV's army was shattered. The Mongols reached the Adriatic coast. The Holy Roman Emperor Frederick II sent warning letters across Europe. Pope Gregory IX called for a crusade. Then, everything stopped. On December 11th, 1241, Ogedei Khan died in Kharkhorum, reportedly after a drinking binge. The generals received word and turned their armies around. There would be a Hurrildai to elect a new Khan, and all senior Mongol leaders had to attend. Europe was left untouched. France, England, Spain. They never saw a Mongol army. Not because they were too strong, but because Ogedei Khan drank himself to death at the right moment. After Ogedei died, the empire entered a difficult decade of succession politics. His widow, Toregenei Khatan, served as regent and eventually engineered the election of her own son, Gurg Khan, as Great Khan, in 1246. Gurg Khan died just two years later, in 1248. Another regency. More political maneuvering. The Mongol system of collective family rule, which Chinggis Khan had designed to prevent any one branch from monopolizing power, was producing exactly the problem it was meant to avoid. No one could agree on anything. In 1251, after considerable political struggle, Monk Khan, the son of Tului, Chinggis Khan's youngest son, was elected Great Khan. Monk was something different. He was disciplined, competent, and genuinely effective at re-centralizing Mongol authority. Under him, the empire functioned again as something resembling a unified whole. Monk divided the major campaigns between his brothers. Kublai went south and east to complete the conquest of Song China. Hulegu went west. Hulegu's first target was the Assassins, the Nizari Ismaili sect that had controlled a network of mountain fortresses across Persia and Syria for nearly 150 years. The word assassin in English actually derives from the legends around this group. They were feared across the Islamic world. Hulegu destroyed their main stronghold, the fortress of Almaty, in 1256. The Grand Master of the Assassins surrendered within weeks. The fortress's famous library, said to contain rare and valuable texts, was destroyed along with it, though some sources suggest Hulegu's scholars preserved what they could. Then came Baghdad. The Abbasid Caliphate had been the symbolic center of Sunni Islam for over 500 years. The Al-Khalifat in Baghdad was not just a political ruler. He was the spiritual leader of the Muslim world, the successor to the Prophet's authority in the eyes of millions of people. The city itself was one of the great intellectual centers of the medieval world. Its libraries, the House of Wisdom, had been accumulating Greek, Persian and Arabic scholarship for centuries. Mathematics, astronomy, medicine, philosophy. Baghdad was not just a city. It was a civilization's memory. The Al-Khalifat al-Mustasim was apparently not a particularly capable ruler. His advisors gave him contradictory counsel. He did not respond adequately to Hulegu's demand for submission. So in January 1258, Hulegu's force, somewhere between 100,000 and 150,000 men, along with a large contingent of Chinese siege engineers, surrounded Baghdad. The siege lasted less than two weeks. On February 10th, 1258, the city fell. What followed is described in the accounts of Persian historian Rashid-ud-Din, who had access to Mongolian court records. He said, the streets ran with blood. The libraries and their contents were thrown into the Tigris River. The water, according to Rashid-ud-Din, turned black with ink and red with blood. Death toll estimates from medieval chroniclers range from 200,000 to 800,000. The Caliph al-Mustasim was executed in a way that honored Mongol tradition around noble blood. He was wrapped in felt or a carpet and trampled to death by horses, so that royal blood did not touch the ground. The Abbasid Caliphate, which had begun in 750 CE, ended in 1258. Just like that, the Islamic world reeled. The great city of Baghdad was left largely depopulated. The agricultural infrastructure of Mesopotamia, canals and irrigation systems that had supported civilization since the ancient Babylonians, was damaged badly and never fully restored under Mongol governance. Then, something happened that had not happened before. The Mongols were stopped. Hulegu pushed further west into Syria. But in 1259, Monk Khan died during the siege of Diaoyu Cheng in China. Hulegu pulled the majority of his forces back east for the succession crisis, leaving only a reduced force in the Middle East under his general Khitbuga, at the Battle of Ain Jalut, Spring of Goliath. In September 1260, in what is now northern Israel, a Mamluk army from Egypt under their commander Qutuz met the reduced Mongol force. The Mamluks were Turkic slave soldiers, a product of the steppe the Mongols originated from, trained as cavalry, experienced and hard. They defeated Khitbuga's force. The Mongols retreated. They would return to the region multiple times over the following decades. But they never broke through into Egypt and North Africa. Ain Jalut proved the Mongols were not unstoppable. It marked the western limit of the Mongol advance permanently. Two of Monk's brothers, Khubilay and Arigboch, both claimed the title of Great Khan and went to war with each other. This was the Tuluin Civil War from 1260 to 1264. Khubilay eventually won. He was proclaimed Great Khan. But his authority was already limited. The Western Khanates, the Golden Horde in Russia, and the Ilkhanate in Persia increasingly operated as independent powers. Some recognized Khubilay's nominal supremacy. Others simply ignored it. By the 1260s and 1270s, what had been one empire was functionally four separate states. The Yuan Dynasty in China and Mongolia, controlled by Khubilay Khan and his successors. The Golden Horde, ruling the Western Steppe, much of Russia and the territory Bat Khan had won. This was the Khanate that would have the longest-lasting political impact, shaping the development of Russia for the next two centuries. The Ilkhanate, ruling Persia, Iraq and the Caucasus under Hulegu's descendants, eventually converting to Islam and slowly becoming absorbed into the broader Islamic world they had conquered. And the Sagadayn Uels, holding Central Asia, an often unstable entity that fragmented further and would eventually produce, in the late 1300s, a ruler named Timur or Tamerlane, who would cause destruction almost comparable to Chinggis Khan himself. These four khanates were not peaceful with each other. The Golden Horde and the Ilkhanate fought bitterly. The Golden Horde's Ber Khan had converted to Islam and was furious about the destruction of Baghdad and the killing of the Caliph. The Sagadayn Uels was constantly in low-level conflict with the Yuan Dynasty's western borders under a challenger named Haidu, who fought Khubilay Khan for 30 years over the title of Great Khan. The dream of a united Mongol Empire under one Khan, fulfilling the divine mandate of Tengger, was over. What replaced it was four regional powers that were unmistakably Mongol in origin, but increasingly shaped by the cultures they governed. The Ilkhanate became Persian and Islamic. The Golden Horde became increasingly Turkic and Muslim. The Yuan Dynasty became Chinese in many of its administrative practices. Only the Sagadayn Uels remained most visibly nomadic for the longest time. This is the great irony of Mongol history. The people who conquered the world by refusing to be absorbed by anyone else, by maintaining their identity as steppe warriors against all odds, ended up being absorbed by every culture they ruled. Within a few generations, they were speaking Persian, Chinese, Arabic and Russian. They were worshipping at mosques and Buddhist temples. The Mongols remade the world, and then the world remade them. Now let's balance the ledger, because the full story of the Mongol Empire is not just destruction. Between roughly the 1250s and the 1340s, a period historians call the Pax Mongolica, Latin for Mongol Peace. The Silk Road was safer than it had been in centuries. The network of trade routes from China to the Mediterranean, which had been fragmented and dangerous under dozens of different rulers, was now unified under a single political system with consistent rules. Merchants and travellers could move across the continent with the protection of the Ortu, or Yam network, and Mongol law. Marco Polo travelled from Venice to the court of Hubilai Khan in China between 1271 and 1295. His account, Whether You Believe Every Detail or Not, describes a world that was genuinely astonishing in its connectivity. He saw things that Europeans had never seen. Paper money, coal burning for heat, the sheer scale of Chinese cities. His book, written after his return, sparked European fascination with the East that would eventually drive the Age of Exploration. William of Rubruck, a Franciscan friar sent by King Louis IX of France to Harkerum in 1253, arrived at the Mongol capital and found a cosmopolitan court where Muslim merchants, Nestorian Christian priests, Buddhist monks and Mongol shamans all coexisted around the same table, competing for the Khan's favour. Religious tolerance was not just a nice idea in the Mongol Empire, it was official policy. Chinggis Khan had established early on that the Mongols would not persecute any religion, partly because he was genuinely pragmatic about the supernatural and wanted divine favour from all possible sources and partly because persecution created rebellious subjects, and he had no interest in managing that. The trade itself was transformative. Goods moved from China to Europe and back. Silk, porcelain, spices, paper, gunpowder, a Chinese invention that entered the Islamic world and then Europe partly through Mongol channels. Ideas and technologies moved the same way. Mathematical knowledge, medical practices, astronomical data, the intellectual cross-pollination of the Pax Mongolica contributed to the conditions that made the European Renaissance possible. So, how do we total up the Mongol Empire? What was the final account? The human cost was staggering. It is estimated that 30 to 40 million people died as a direct result of Mongol conquests, famines caused by the destruction of agricultural infrastructure and associated plagues. Some demographic historians have calculated that the world's total population actually declined during the height of the Mongol expansion. Parts of Central Asia, Northern China and Persia took generations to recover. Some regions and cities were simply never rebuilt to their pre-Mongol scale. The political map of the world was fundamentally redrawn. The Abbasid Caliphate was gone. The center of Islamic power shifted to Mamluk Egypt and eventually to the Ottoman Empire. Russia, cut off from the Byzantine world and dominated by the Golden Horde for over two centuries, developed a political culture shaped by that relationship. Some historians argue that certain aspects of Russian autocracy and its relationship to central authority were influenced by the Mongol model. But the Mongols also created things. The Zasag Khul, Genghis Khan's legal code, was one of the first attempts at a written law system among the Mongol people. The Ortu, or Yam postal network, was the largest communication system the world had seen. The meritocratic military structure was genuinely revolutionary. The cultural synthesis they enabled, the blending of Persian, Chinese, Arabic and Mongol artistic and intellectual traditions, produced remarkable works. The illustrated manuscripts of the Ilkhanate, the architecture of Kharkhorum and Shandu, the paintings of the Yuan court. Now, there is one more chapter we have not opened yet. Because when the Mongols finally settled down, and actually tried to rule one of the world's most complex civilizations, China, something fascinating happened. Kublai Khan's Yuan dynasty is a whole story on its own. That video will be up in a few days. If this video was worth your time, hit the like button, subscribe, and I will see you in part two.