WAR AND PEACE IN THE MONGOL EMPIRE

One of the crucial elements of Mongol success was the systematic training of commanders. For decades, the Mongol Empire maintained a remarkably consistent level of generalship, something rarely seen in medieval societies. In most cases, states might produce a handful of competent commanders, perhaps a few who excel tactically or strategically, and then go generations before finding their equals. The Mongols, by contrast, produced not only consistency but also exceptional figures such as Sübedei, Jelme, and Muqali. These were three of Chinggis Khan's most brilliant and loyal generals and instrumental in founding and expanding the Mongol Empire. Their talents far exceeded what one would normally expect from a single state.

Now, the political aspect is also very important. Chinggis Khan needed an ideology capable of binding together disparate groups. The familiar notion that the Mongols were destined to conquer the world, that Köke Möngke Tengri, the ‘Eternal Blue Heaven’, had granted Chinggis Khan’s ancestors dominion over the earth emerged later. In my view, this was largely a creation of Ögedei Khan, his third son and the second Great Khan to consolidate and expand the Mongol Empire, and subsequent generations, not something Chinggis Khan himself truly believed.

If one closely follows his campaigns, it becomes clear that he was not pursuing global conquest. His primary objective was to stabilize Mongolia and prevent others from undermining what he had created. To achieve this, Chinggis Khan fundamentally reshaped steppe society. He dismantled the old system of elite lineages. While many of these groups survived, they were reorganized, demoted, or replaced. Society was restructured into decimal units—tens, hundreds, and thousands—forming the backbone of the military.

Crucially, many commanders appointed to these units were commoners who had earned his trust through demonstrated ability. Soon, Chinggis Khan began to value merit over lineage. This did not, however, mean that lineage disappeared entirely, but new paths to power emerged. At the same time, he dismantled the traditional nöker systemiThe nöker system was a foundational Mongol institution of sworn personal allegiance, binding warriors as ‘companions’ to a leader, creating the core of the imperial elite. of personal bonds, having experienced its limitations firsthand during his own early career as a follower of Toghrul Khan of the KereitiThe Kereit were a powerful Turco-Mongol confederation, rivals to Chinggis Khan before their defeat and absorption into his empire.. Although traces of the old system remained, society was increasingly organized to sustain the military structure.

The Mongol military machine, therefore, cannot be separated from the political ideology that made it possible. Chinggis Khan adapted existing practices, borrowed from societies he encountered, and adjusted them to the conditions of his time.

The Mongols relied heavily on engineers and specialists throughout their empire, but this was not how things began. Initially, they were not very good at siege warfare. Beyond blockading a city, they had little understanding of how to conduct a proper siege, and their equipment was limited to basic tools such as ladders and, at most, a rudimentary concept of battering rams.

When the Mongols invaded the kingdom of Xi Xia in what is now northwestern China, they eventually captured the capital at Yinchuan by constructing a dike. At the time, however, they lacked sufficient engineering experience, and the structure was poorly designed. When it collapsed, it flooded not only the city but also the Mongol camp. According to the sources, this episode convinced the defenders that the Mongols were prepared to go to extreme lengths, even at great cost to themselves, and Xi Xia subsequently surrendered.

And from this, the Mongols were probably able to gain some engineers. But the decisive transformation came with the invasion of the Jin Empire. Mongol success encouraged defections, including specialists with engineering skills, and the Mongols showed a keen interest in incorporating such expertise.

By the time of the Mongol invasion of the Khwarazmian EmpireiThe Khwarazmian Empire was a powerful Central Asian state annihilated by Chinggis Khan's invasion in the thirteenth century. in 1218, engineers were no longer exclusively Chinese, Jin, or Khitan. Mongols themselves were commanding engineer corps and actively designing siege works. Talent, regardless of origin, was quickly absorbed into the Mongol military or attached to the households of Mongol princes. This openness operated across the empire. Under Kublai Khan, Muslim engineers were brought from the Middle East to China, introducing new technologies such as trebuchets that proved decisive in the sieges of Xiangyang and Fancheng. And soon, expertise flowed in both directions.

Although Mongols were increasingly trained in these skills, the scale of Mongol operations ensured a constant demand for artisans, craftsmen, and engineers. Siege warfare became not an obstacle, but another domain in which the empire learned, adapted, and expanded.

I am wary of using the word ‘inevitable’. Things would have been different, but I am not interested in counterfactual history that asks, ‘What if this had happened instead?’ What matters is that Chinggis Khan was not trying to conquer the world. His primary goal was to secure Mongolia.

The conflict with the Khwarazmian Empire emerged from a combination of circumstances. By this point, Chinggis Khan had expanded into what is now Kazakhstan while pursuing the Naimans and the Merkits, rivals of his, who had fled Mongolia. Many of the Naimans sought refuge in the Qara Khitai Empire, where they eventually seized power.

Initially, Chinggis Khan had no intention of confronting Qara Khitai. Part of this reluctance stemmed from ongoing concerns elsewhere, but it was also linked to the prestige of the Gur-khan, the ruler of the Qara Khitai Empire, meaning ‘universal khan’ in the Turkic languages. Qara Khitai, a successor state of the Liao Empire, retained considerable legitimacy and symbolic authority, even in decline. In the memory of Mongols and other steppe peoples, it still carried a sense of imperial grandeur.

It was in this context that the Mongols first encountered the Khwarazmians while pursuing the Merkits. That encounter ended inconclusively. Chinggis Khan had explicitly instructed his sons Jochi and Sübedei to avoid wider conflict and focus solely on destroying the Merkit. These intentions were communicated to Shah Muhammad, the son of Tekish and the last major shah of the Khwarazmian Empire, but he was eager to go to war. Possibly because of the loot, possibly because of his own prestige, it was clear that he thought very highly of himself and his own abilities. He viewed the Mongols as pagans and saw confrontation as a means of reinforcing his legitimacy as a Muslim ruler, even while he remained a subject of Qara Khitai.

A further turning point came in 1216, when the Mongols invaded Qara Khitai following the usurpation of the throne by the Naiman prince Küchlüg. This conquest brought the Mongols into direct contact with the Khwarazmian Empire.

Once their borders were shared, relations had to be managed between the two. The Mongols were interested in trade. Their first commercial contact with Khwarazm occurred when a Khwarazmian caravan was sent to the Jin Empire, partly for trade and partly to gather intelligence. In the course of this exchange, they encountered the Mongols.

The Mongols sent back another caravan. This mission ended in catastrophe when the caravan was massacred. Shah Muhammad’s actions were shaped by ambition as much as by miscalculation. He increasingly saw himself as a second Alexander the Great, reinforced by advisers who told him what he wished to hear.

Of course, Muhammad had his own imperial aspirations. In that sense, conflict between the two powers was possible, even likely, but it was not imminent. It could have been postponed for some time. Chinggis Khan had no immediate interest in invading Khwarazm. He was deeply engaged in campaigns in North China and had only recently suppressed unrest in Siberia.

Muhammad Shah, however, understood this situation and chose to act. He anticipated a Mongol response and appears to have believed that an attack would expose what he regarded as a fundamental Mongol weakness: an inability to conduct prolonged warfare against fortified cities. He expected their forces to falter. Had this strategy succeeded, Muhammad might then have turned on Qara Khitai, expecting to be welcomed as a liberator by Muslim populations. Instead, the outcome was disastrous.

From the Mongol perspective, one commonly cited explanation was the lack of sufficient pastureland in Syria to sustain large forces over the long term. Even if the region could be invaded and conquered, holding it permanently posed serious logistical challenges. I find this argument somewhat unconvincing, as the Mongols had overcome similar constraints elsewhere.

But one of the key reasons is because the Mamluk SultanateiThe Mamluk Sultanate was a medieval realm in Egypt and Syria, ruled by a military caste of former slaves, famed for halting the Mongol advance., despite its own greatness and its own worth, was what we would now call small potatoes compared to the other enemies of the Ilkhanate in Persia, which was often fighting the Jochid ulus or the Chagatai ulus in Central Asia.

The Mongols would basically deal with the Mamluk Sultanate, Syria, and Egypt, in their spare time when they were not busy waging campaigns in Central Asia or the Caucasus Mountains. But from the other side, we also have to take into account what the Mamluks were doing.

From the Mamluk perspective, the situation was fundamentally different. For them, this was a struggle for survival. A Mongol victory would have meant destruction or enslavement, even if some were eventually incorporated into the Mongol military. Faced with that prospect, the Mamluks devoted extraordinary resources to defence.

Beginning under Baybars [Tooltip: Sultan Baybars was the formidable Mamluk ruler who strengthened the sultanate, famously defeated the Mongols at Ain Jalut.], they constructed a flexible defensive system along the Euphrates, deliberately destroying pastureland to prevent the Mongol armies from sustaining large numbers of horses. They also developed rapid communication networks that allowed troops to be mobilized quickly. During periods of reduced Mongol pressure, Baybars systematically eliminated Mongol allies and vassals in the region, including Bohemond VI of Antioch and Tripoli, and launched repeated campaigns against Cilicia, or Lesser Armenia, a loyal Mongol client. He even pushed into the Seljuk Sultanate of Central Anatolia to neutralize potential threats.

The Mamluks themselves were tremendous warriors. They faced not only the Mongols but also the possibility of renewed crusading expeditions from Europe, which would most likely have targeted Egypt. For decades, this dual threat shaped Mamluk policy and military organization. Crucially, the Mamluk Sultanate never attempted a sustained invasion of Ilkhanid territory. This restraint proved wise. While raids into Cilicia did occur, they followed the systematic dismantling of Mongol influence there. The Mongols, meanwhile, increasingly diverted their attention elsewhere.

Although the Mongols briefly reoccupied Syria under Ghazan Khan, the ruler of the Ilkhanate state, they ultimately withdrew, concluding that the region could not be held securely or profitably over the long term. Other priorities soon eclipsed the Levant, which no longer justified the costs of sustained conquest.

Japan mattered to the Mongols primarily because of its economic connection to the Song Empire. When the Mongols launched their first expedition in 1274, it was not intended as a full-scale conquest. Although it is often portrayed that way, the operation was limited in scope. The Mongols struck Hakata Bay, the main hub of trade with Song China, achieved their immediate objectives, and withdrew.

At the time, Mongol progress against the Song was slow. Song China was an extraordinarily wealthy state, capable of absorbing battlefield defeats while continuously replacing troops, fortifications, and equipment. So it was important to also hurt the Song Empire economically, and that led to the first invasion.

After the conquest of the Song, the Mongols’ objectives shifted. The belief that the Mongols were destined to rule the world—that Köke Möngke Tengri, the Eternal Blue Heaven, had granted them this mandate—now played a greater role. For Kublai Khan, renewed campaigns also carried a personal dimension: the desire to match the stature of Chinggis Khan. Japan, known for its warriors and resources, became a logical target, especially after the killing of Mongol envoys and the presence of a ruler claiming imperial status.

Now, did the weather affect the outcome? Well, the answer is both yes and no. While storms damaged Mongol fleets, Japanese resistance evolved rapidly after the first invasion. There were persistent expectations that the Mongols would return, and, much like in the case of the Mamluks, defence against a renewed invasion became a defining element of Japanese identity. Anticipating future attacks, Japanese society reorganized itself for defence. Warfare shifted away from individual combat toward collective action, fortifications around Hakata were strengthened, and military organization was restructured.

A third invasion was planned but ultimately abandoned. Advisers warned Kublai Khan that the costs would be excessive and could provoke unrest in Korea and parts of China, where shipbuilding and manpower were being requisitioned on an unprecedented scale.

In Japan, the Mongol invasions became a formative historical experience, shaping defensive identity for centuries and later re-emerging in modern national narratives. To explain the Mongol failure solely by reference to bad weather is therefore misleading. It also has a lot to do with the efforts of the Japanese to defend. They learn from that first encounter, much like the Mamluks have done.