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Undoubtedly, the largest empire in the existence of human history was the Mongol Empire, once a hodgepodge of warring nomadic tribes from Central Asia before banding together under the banner of Temujin, better known as Genghis Khan.

But what was the key to the Mongol Empire's size? Was the horse, the most ideal creature to use for long-distance travel, the exclusive reason? Or were there other factors involved?

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    "Undoubtedly, the largest empire in the existence of human history was the Mongol Empire". British Empire says hi. Look at this link: en.wikipedia.org/wiki/List_of_largest_empires
    – Brasidas
    Commented Jun 29, 2016 at 20:24
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    @Brasidas maybe we can qualify and be accurate as the largest consecutive or pre-colonial empire.
    – taninamdar
    Commented Jun 30, 2016 at 5:56
  • 3
    @Brasidas, by % of world population, the Mongols have the British Empire solidly beaten (but are eclipsed by the Qing). By % of world land area, the British margin of victory is less than the uncertainty in the borders of the Mongol Empire (just where do you decided to draw the line in the Arctic tundra?)
    – Mark
    Commented Jul 1, 2016 at 0:01
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    Most questions that ask for an exclusive reason are flawed; seldom is there an exclusive cause for an historical event. Causes for singular historical phenomena are generally book length answers. Second, this is an X:Y/"amirite" question. The final paragraph asks for confirmation that the "most ideal creature" is the exclusive reason.
    – MCW
    Commented Oct 4, 2016 at 13:33
  • 3
    I would agree that the area shown is large, but not, perhaps, as large as one might believe. The projection of the map type used makes the dimensions seem larger than reality.
    – CGCampbell
    Commented Oct 4, 2016 at 21:35

7 Answers 7


There are a number of tactical and strategic reasons that the Mongols were successful.

  1. Core of strong leaders:

Not only were the upper levels of military leadership strong, but the mid-level and lower level leadership was also very strong.

  1. Flexibility of tactics:

They used whatever means necessary to defeat their enemies, including using direct confrontation by large forces, using of smaller forces in guerrilla tactics, deceit and subterfuge, etc. During an attack, local commanders had a broad outline of the campaign strategy, and also had the freedom to achieve their tactical goals as they saw fit.

A common tactic was to intentionally tire their opponents horses. First they charged into battle, then feigned retreat, enticing their opponents to pursue. Once their opponents' horses were tired, the Mongols would switch to fresh horses, and return and massacre.

It is important to note that the Mongols very much preferred their opponents to surrender, and most conquered areas came to be controlled in this way.

  1. Technology:

Mongolian made crossbows and bows were the best in the world at that time. They were composed of compound materials and took a number of years to manufacture.

They additionally kept Chinese engineering units in the field for events of siege warfare.

  1. Public Relations:

Mongols treated surrendering populations very well; as they economical favored merchants and poor farmers over elites, the general population was well disposed towards them. Conversely, the Mongols "made examples" of opponents who fought back, and did not hesitant to brutally torture and kill those who took the field against them.

They additionally deceived commoners and merchants about the size of their army; while it was modestly sized, they led their opponents to believe that they were had an enormous fighting force (a 'Horde'). Not only did this intimidate their enemies and the surrounding populace, it also led to tactical errors on the part of their enemies. Specifically, enemy armies expected many unskilled fighters, and instead they encountered smaller, sophisticated fighting forces.

  1. Military Intelligence Mismatch:

The Mongol data collection methods were very strong. As merchants benefited greatly from Mongol expansion, merchants eagerly provided information about the Mongol's enemies. As merchants knew the ruling classes and geography of to-be-territories, the shared information was of great value.

The Mongol opponents, however, knew primarily what the Mongol PR told them: that in surrender they would be treated well, if they fought they would be not just defeated but annihilated, and that the Mongol army was enormous.

  1. Strong economic growth in conquered areas:

The Mongols replaced the ruling elites in conquered areas, subsequently lowering tax burdens on farmers, artisans, and merchants. They also encouraged trade by establishing safe, easily travel-able trade routes across Asia, allowing safe trade for the first time in history between China, East Asia, and Persia, the Muslim world, and Europe. As they controlled a huge area, their lower taxes resulted in a huge revenue stream, to allow very strong logistical support.

  1. Supply and Logistics:

The Mongol forces stayed well supplied by both living off the land, maintaining a relatively small fighting force, encouraging merchant traders in conquered areas, and a large number of horses for direct logistical support during campaigns.

They also had very strong communication between forces, using relays of riders.

  1. Espirit du Corps:

The fighters in Mongol units were very tough men - they grew on the plains as nomads, and were accustomed to thinking independently and solving problems, developing strong endurance while traveling with excellent horsemanship, while having a cultural tradition of respect for wise authority.

In summary, Mongols were a very well organized, strategically and tactically strong fighting force, with a number of reasons for extensive success.

Sources: While the wikipedia article is ok, I really respect entry in the Encyclopedia of Military History by Dupuy. They provide a very non-biased, factually based account of Mongol success. The anti-mongol propaganda, developed by the conquered elites in China, SW Asia, and Eastern Europe is definitely skewed, and still skews modern Mongol History until even today. In this regard, Dupuy did a fantastic job in conveying why the Mongols were successful conquerors.

Other thought:

The trade that flourish during Mongol rule gave western Europeans a taste for the luxury goods of East Asia; when the empire collapsed in the late 1300's, prices went up due to disruptions in trade, and the desire by European elites for luxury goods led to the beginning of colonialism and European expansion.

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    Comments are not for extended discussion; this conversation has been moved to chat.
    – T.E.D.
    Commented Jul 11, 2017 at 13:26
  • This maked too many claims which are unsubstantiated. Also, Timur definitely did not 'conquer India and establish Mogul Empire'.
    – Rohit
    Commented Dec 21, 2019 at 9:31
  • @Rohit What's wrong with the cited source? Commented Dec 21, 2019 at 14:53

This is indeed an interesting and difficult question. Mongols defeated almost all states around them, and they certainly had no technological advantage or any superiority in the weapons. But this is not the first case in history when nomads defeated the more technologically advanced settled civilizations. (One historical example is the Hunns, and parts of China were conquered by the nomads many times).

The conquest of Genghis Khan and his followers was just the greatest (of all similar nomad conquests) in terms of territory. But notice that it was short lived: this huge empire was split into several parts in 2 generations after Genghis Khan.

The general advantages which the nomads had over settled people is that they were extremely tough: they could survive the degree of deprivation which the armies of settled peoples could not. And war was the only occupation of almost every male. So they could create large armies, though they almost always were smaller than those of their enemies. But these are general advantages of the nomads.

What makes the Mongol stand out among other nomad conquerors, was an extremely effective organization. It seems that this is due to the extraordinary abilities of their leader, Genghis Khan. He was able to achieve a strong discipline, in a large army, and appoint outstanding commanders. (They say that Subudai-bahadur won more than 100 pitched battles and lost none. So he was by far the greatest military leader in history. And Jebe was probably the second). And none of Genghis Khan top commanders or close relatives ever betrayed him, another unique thing in history.

His adversaries did not have this degree of cohesion, and had no social mechanism for appointing the most talented officers on key positions. In most societies of that time, commanders were appointed according to their birth, or noble origin, or court intrigues. In the Mongol army, promotion was clearly based on the merit. Subudai and Jebe were of very modest background.

Mongols were able to adapt all necessary inventions from neighboring countries to their advantage. I recall that in the beginning they had even no writing. (The writing was adapted from the Uighurs). They had no idea how to take walled cities. Before they attacked China. After that they adapted Chinese technology and Chinese TECHNICIANS (!) to operate it. This only shows the outstanding abilities of their leaders.

Another thing I want to mention is the ability and desire of Mongols to learn. Their superior military intelligence is frequently mentioned. The Russian chronicle, for example says "Came some Tartars, who they are, and where did they come from, nobody knows". The attitude of Western Europeans was not much different.

This is in sharp contrast with Mongol's attitude: they KNEW where they were going, they knew all details about the situation in Europe when they came there. They knew what they needed to know. They sent spies. They did meticulous planning. Again this has to be credited to their supreme leadership.

EDIT. I was asked to add references. The main primary source for the events before the death of Genghis Khan is the so-called Secret History of the Mongols. The standard English translation with comments is this: https://www.amazon.com/Secret-History-Mongols-Mongolian-Thirteenth/dp/9004153640 Many other translations in many languages are available (some free on Internet), http://altaica.ru/e_SecretH.php Based on this, and on somewhat later Arabic (Rashid-ad-din and others) and multiple Chinese histories, many books are available. A good one, covering the same period (before the death of Genghis Khan) is this: https://www.goodreads.com/book/show/983069.Conqueror_of_the_World It collects information from primary sources, with some reasonable comments, and makes a good reading. For those who prefer movies, there is a Mongolian-Chinese TV series called Genghis Khan (2004). I do not know in what languages it is available, I watched it in Russian. It is quite faithful to the "Secret History" in showing the events, but they somewhat gloss over the episodes which characterize Genghis Khan negatively (from modern point of view) and emphasize the episodes where he looks good. Nevertheless they do show everything mentioned in the Secret History. For example, they do not show the mass slaughter episodes, but one can easily guess what happens behind the screen. There is a biography of Subudai, Gabriel, Richard. "Genghis Khan's Greatest General Subotai the Valiant". University of Oklahoma Press, 2004, but it is not very good on my taste. The author just collected all sources that mention Subudai. I do not know any monographs about other top commanders (Jebe, Jelme, Mukhali, Khubilai). Not the Khubilai Khan, grandson of Genghis Khan, first Yuan emperor of China, but another Khubilai, one of the "Four Hounds" of Genghis Khan. Most authors, including Wikipedia confuse these two Khubilais.

EDIT. Let me add one little remark to this long answer. We know that it took much more time and efforts of Genghis Khan to conquer and unite all Mongolian tribes, then to defeat North Chinese states and Khwarezm. In some sense, uniting Mongolian tribes was a greater feat. And certainly he had no advantage in weapons or technology when he did this. Expedition to Eastern Europe by his descendants was a small episode by comparison.

  • Did they, or did they not have access to Chinese siege technology when they expanded west? Did it provide any advantage in their westward expansion? Why do you feel that this was not a "technological advantage" for the advancing Mongolian offensive? Most histories of name access to Chinese siege technology as of critical importance. Commented Oct 5, 2016 at 2:22
  • @axsvl77: Yes they did use Chinese technology when they moved West. But their most important and stunning achievement was conquest of China, which started earlier. It seems that, unlike their adversaries, they were able to learn. Quickly. And use not only technologies but also human resources of conquered countries for further conquests.
    – Alex
    Commented Oct 5, 2016 at 2:32
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    I have heard similar things before, but would appreciate references linked or mentioned. Also it's worth noting that the Mongolians were a pluralistic society, and this was a deliberate decision to respect people of different colours and creeds. This allowed them to increase the size of their military. Also, not only did they have spies, but they had a postal service, so combine the two and you have excellent communication across the empire.
    – user17846
    Commented Oct 5, 2016 at 9:15
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    @inappropriateCode: I added some references.
    – Alex
    Commented Oct 5, 2016 at 20:48
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    Everyone can collect sources. Of a good historian I expect analysis.
    – Alex
    Commented Jul 10, 2017 at 7:35

Most of that huge area was and until today still is scarcely populated and thus not really "controlled", but rather "owned". Control is executed over people, cities, communities, important landmarks, important resources by the presence of military, militia and gov. institutions. And while the Mongols certainly had a lot of these under their control, most of their empire was desert and empty steppes with some small nomad peasant families here or there, over which they never had any real "control". Do not forget, that the Mongols never had the abilities to constantly monitor and evaluate of what is going on in that huge area. Modern huge countries with deserts and/or steppes like Russia and China do have these possibilities thanks to technical advancements.

A good way to demonstrate the difference between control and ownership are the modern day maps of the so-called Caliphate of the so-called Islamic State.

Study of War Map

Modern day map of the so-called Caliphate of the so-called Islamic State.

Here, you can see how the political power is not holding a bulk area but rather populous centres, the roads between them and some other important landmarks. The void in between, in this case desert, is not really "in control" by the power, simply because there is nothing to control. This is a more accurate picture of how political powers, especially in the past, did look. But since we do not have so much information in detail about what were the real controlled map parts, we tend to ignore the fact that not really all of the area was under control.

PS: Also, I wanted to mention that the mongol empire was not the biggest empire in the world. By owned area, it was the British Empire and by individuals controlled over the total humanity population at their time, it was the Persian Empire under the Achaemenids.

  • That's unnecessarily complicated
    – D J Sims
    Commented Jun 29, 2016 at 21:29
  • Not only that, it doesn't answer the question. Commented Jun 29, 2016 at 22:17
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    The purple area in the lower left hand part of the map, combined with China, was much of the civilized world. Sure, plenty of wasteland and farm land was in the Mongolian Empire. But plenty of people and cities too. Commented Jun 30, 2016 at 1:38
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    Yes, much of the land area they controlled was empty. But they also controlled some of the most densely-populated parts of the world: China, modern Burma, Mesopotamia.
    – Mark
    Commented Jun 30, 2016 at 23:55

1/ the fragmented and disunited nature of China of the time. The ability of the Mongols to fight only part of China and acquire Chinese allies was absolutely crucial for the Mongol conquest. Without this the Mongols would not have succeeded. This is a key factor in Mongol success that is often overlooked. Against a strong unified China the Mongols would not have been successful.

2/ Strong unified political leadership (contrast with the Chinese). The Mongol empire quickly started to decay once the unified leadership fell away. Politically the organisation and structure was not up to an enduring empire.

3/ Discipline/organisation. This was what set the Mongols apart from other horse nomads. Militarily in tactics they was no real difference between the Mongols and other horse nomads. They ran the same basic playbook, just with better leadership, discipline and organisation (which were often quite poor with horse nomads).


Instead of a long list of factors, it actually comes down to one point: military. They were the superpower from 13th century onward and had the best military, by which I mean Operational Art. This is from the Air War College of US Air Force (see link before):

Overview of Operational Art

Joint Force Commanders (JFCs) employ operational art, in concert with strategic guidance and direction received from superior leaders, in developing campaigns and operations. Operational art is the use of military forces to achieve strategic goals through the design, organization, integration, and conduct of strategies, campaigns, major operations, and battles.

Operational art helps commanders use resources efficiently and effectively to achieve strategic objectives. Without operational art, war would be a set of disconnected engagements, with relative attrition the only measure of success or failure. Operational art requires broad vision, the ability to anticipate, and effective joint and multinational cooperation. Operational art is practiced not only by JFCs, but also by their senior staff officers and subordinate commanders.

In terms of pitched-battles, the Mongol army was more than 700 years ahead of other armies (i.e. rest of us). The other armies never understood why they kept losing and the first 'Western' army that did were the USSR during World War II (influence from Golden Horde?): doctrine of deep battle.

Only in the last few decades, with better research on Mongolian military and history, did modern armies finally begin to appreciate the Mongol generals' superiority:

To be clear, I am not saying that no other military leader since the Mongols had an ability in Operational Art. For instance, General Matthew Ridgway clearly demonstrated this during Korea War, 1950.

  • Not sure why this was downvoted but I'll take a guess: Operational Art seems vaguely defined. Operational art is the use of military forces to achieve strategic goals through the design, organization, etc. So basically, it's just the use of military force to achieve your goal. Every successful battlefield commander therefore would have Operational Art. I upvoted this post because it has a lot of references, but I don't necessarily agree with the answer. One thing we need (but I don't think exists) is a record of actual battle progression with Mongolian maneuvers...
    – DrZ214
    Commented Jul 10, 2017 at 4:59
  • ...which I don't think exists because, first of all, the Mongolians were all cavalry and very fluid in their maneuvers. It's not like traditional battle lines of phalanx or chorots, and then they march into each other and one charge or flank and it's over. 2nd, to my knowledge the Mongols did not make detailed records of every battle, but more like basic records of each campaign. 3rd, any record from the western, Persian, Chinese side would have a hard time accurately recording/remembering such a fluid battle style never before seen (by them). 4th, Mongols used deception quite a lot...
    – DrZ214
    Commented Jul 10, 2017 at 5:05
  • ...and had a reputation for appearing out of nowhere, when in reality it might be the same Mongol group that attacked elsewhere just a half-hour before. They also lit excessive campfires and traveled in very broad lines, just to make their numbers appear bigger. I'm not sure if Delhi Sultanate was intentionally exaggerating the Mongol numbers to 100k or 200k, or if they really did believe that due to successful deception. Anyway, to sum up, I think we need detailed records of a Mongolian battle in order to see what their "Operational Art" really was, but I think we don't have it.
    – DrZ214
    Commented Jul 10, 2017 at 5:12
  • On Operational Art, yes, it does sound too vague (to be useful -- the definition, not the concept). And if the USAF cannot explain it satisfactorily, I won't even bother trying here. No, not every battlefield commander has it and many of the later Noyans (Generals) did not have it either ... from what I've read of their Campaigns during time of Mongke and Kublai. MacArthur & team certainly did not have it in Korea (Halberstam's Coldest War said) but Ridgway did ... so I do believe it is an elusive but crucial element for commanders. Not all has it.
    – J Asia
    Commented Jul 10, 2017 at 6:18
  • The other one (most might disagree with) is USSR, as opposed to the Allied Powers. But, the source for this point was Richard Gabriel, who was then a professor with the War College. Who am I to say otherwise. In fact, after doing some research (incl interviews), it checked out. Hence, I agree with the Prof.
    – J Asia
    Commented Jul 10, 2017 at 6:22

Here's an article that explains the reasons for the rise of Mongol Empire and how it managed to get so big. Hope it helps.


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    As links and articles can change and be deleted, it would improve your answer if you included some of the key points from the linked page in it.
    – Steve Bird
    Commented Sep 5, 2018 at 14:36

By intervening in the internal affairs of other large empires (China, Persia, Kievan Rus) etc., and winning.

China, for instance, was split between the Jin and Song dynasties. So the Mongols allied with the Song against the Jin, and after defeating the Jin, gathered up Chinese "not Songs" against the Song.

In Persia, the Mongols benefited from the fact that the Sultan of Kwarazem was at odds with his "boss," the Caliph of Bagdad. Each of them had to worry about the other, as well as the Mongols, so the Mongols beat both.

In Russia, it was the "other way." They had beaten a Turkish people called the Cumans around the Caspian Sea. The King of the Cumans was the father in law of the King of the Galicians, (which later became part of the Ukraine), and he dragged his son in law into a war with the Mongols, and both lost.

  • the King of the Cumans ... the King of the Ukrainians Neither the word "ukrainian" existed in the 1200s, nor there were any kings there.
    – Matt
    Commented Oct 5, 2016 at 5:45
  • Also Kotyan's son-in-law was Mstislav "Lucky" (Knyaz of Galicia), not Mstislav "Old" (Great Knyaz of Kiev). Mstislav "Lucky" managed to survive the Battle of Kalka.
    – Matt
    Commented Oct 5, 2016 at 5:48
  • Ok, changed that to "King of the Galicians, (which later became part of the Ukraine),."
    – Tom Au
    Commented Oct 5, 2016 at 21:32
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    Galicia became part of the Polish kingdom. First time when (a half of) Galicia became part of the Ukrainian SSR (which was part of the SU) was 1939, that is 700(!) years after the Battle of Kalka. Even now a little part of historical Galicia belongs to Poland.
    – Matt
    Commented Oct 6, 2016 at 4:21
  • King of the Galicians Again you seem to confuse Mstislav "Lucky" (who originally was Knyaz of Novgorod and became Knyaz of Galich only for a little time and btw. with the help of his father-in-law) with Knyaz Daniil Romanovich who had ambitions for reuniting Galicia and Volyn and proclaiming himself Tsar of Rus. Mstislav had nothing to do with that.
    – Matt
    Commented Oct 6, 2016 at 4:27

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