In the mid 13th century, France was without a doubt the richest land of the West. Inside its modern borders there were perhaps 18 million people, and maybe more, at that time perhaps 1/5 of all the people in Europe. By contrast, all of the lands of the Rus, including modern Belarus and Ukraine, had maybe 6 million people. Let us say, instead, that the Ukraine is as populous and wealthy as France in the year 1240. It has roughly the same size and is likewise covered in arable land.

In 1240 the Mongols came out of the East and sacked Kiev, burning it to the ground, ending its days as the leading center of the Eastern Slavs. Much of Ukraine, which had since antiquity provided grain exports to Classical Athens and later Constantinople, was depopulated, and land use reverted from farming to nomadism. Lands where once indigenous farmers had grown wheat, by the 15th century had become a battleground between Cossack and Tatar. The once distinct Slavic cultural groups were subjected to Polish, Lithuanian, and eventually Russian domination.

But what if the Mongols had come upon a wealthy and populous land like France at the edge of the steppes. Would the Mongols have been able to completely over-run the territory and depopulate it as happened historically?


  • France had a lot of people. Surely, China had over 100 million people when the Mongols conquered it; but at the time China had perhaps 7 times as many people as France, while today China has 18 times as many people. France was probably one of the most densely populated parts of the world in the early 13th century.

  • France was not an empire; it was a decentralized polity with a strong local nobility. Several major dukes and counts controlled territories with populations of a million or more. Furthermore, France was Christian (as was the Ukraine) and the local nobility would not accept a heathen's right to the throne. If the Mongols seized the capital and killed and supplanted the King, the previously mentioned independent nobility would have to be compelled to submit, one at a time.

  • France had a lot of stone castles. This is the real meat of the question, and something that set Western Europe apart from the rest of the world in 1240. Normandy had at least 27 stone castles in 1240, as listed by Wikipedia. There are 14 listed for Brittany, 13 in Picardy, and 14 in Ile de France. Extrapolating that number out to the the whole country, area wise, gives us an estimate of at least 500 stone castles. That is not counting ruins not listed in Wikipedia or wooden castles.

  • Assume that the historical internal pressures affecting the Mongols continued. Batu Khan wanted to contend for the title of Great Khan in 1242, an event often credited with saving Europe from the Mongol; and there were appealing lands to be plundered in the Middle East as well. Batu never returned to Hungary and Poland, where he had been successful in 1241, because he was pre-occupied invading Anatolia. On the other hand, a much wealthier Ukraine may have been a much more tempting target...


Given what we know about Mongol tactics and successes in conquering densely populated areas, areas with decentralized local control, and stone fortifications, would the Mongols have been able to completely subjugate a France-like nation located where modern Ukraine is? Or would an intransigent local nobility and surfeit of stone fortifications have allowed local autonomy to survive for a decade or two until Mongol power waned?

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    $\begingroup$ I'm not sure you actually could have a France-like nation situated where Kiev is. Sure, southern Ukraine has lots of good farm land and a history of fighting Vikings (although not as successfully), but it doesn't have ports on the two most important seas plus three major rivers, a legacy of Romanization going back to the start of the Empire, stable trading partners right next door, natural borders to defend against the more dangerous neighbors, … So I think you'd have to rewrite a lot more history to even ask the question. $\endgroup$
    – abarnert
    Aug 28, 2018 at 1:35
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    $\begingroup$ The Mongol expansion was on the verge of pushing into Europe proper when the then Khan died and they turned away to deal with the imperial succession. If that hadn't happened the Mongols might continued on and even conquered 13th century France too. The Mongol fighting forces were superior militarily to their European opponents. A France-like Ukraine? Easy! The rest of Europe? Very likely. $\endgroup$
    – a4android
    Aug 28, 2018 at 2:19

4 Answers 4


Entirely Possible

Mongols besieged and conquered cultures that were very advanced and established throughout Asia. They managed to subjugate cultures that were arguably larger, more powerful, wealthier, and more technologically advanced than France was at the time.

Fortifications Would Not be a Major Factor

Mongols actually specialized in sieging fortified cities, and were particularly well skilled at engineering siege engines. Actually, that is to say, they were particularly good at enslaving Chinese and Persian siege masters and skilled craftsmen and forcing them to construct said siege engines. They utilized ballistae, trebuchets, traction catapults, and an assortment of other goodies. In the battle of Japan Mongol forces are even historically depicted making use of cannon, crude guns, and early grenade type thrown explosive devices. This being the case fortifications in France probably wouldn't have bothered the Mongols very much.

Mongol's Already Defeated European Castles

The Knights of Rhodes were a sub-group of the knight's Hospitaller in the holy land. They were comprised mainly of french and Italian men with a mixture of other christian Europeans. When one of Genghis Khan's descendants Timur decided to take their holdings at Smyrna (A city in what would now be considered southern turkey) the Italian and french defender's were confident that their fortress was impregnable. After two days of bombardment and mining of the walls the fortress was collapsed on top of the defenders. Any surviving members were massacred or fled by sea, when ships bringing aid to the city approached they were bombarded by the severed heads of the less fortunate members of the city and fled as well. Considering that when mongols came up against the european style of fortress building and defense it only took them two days to tear it down it would seem that mongols were not highly impressed by walls and towers.

"Mongol" Armies

While mongols were fierce and cunning fighters with commanders who had a very characteristic and defining grasp of psychological warfare the mongol armies really weren't just little guys on horses with bows. Due to the rather vague nature of their native shamanic beliefs they were very willing to adapt the cultural practices and traits of those they conquered. They proved highly successful at assimilating the people they conquered into their armies and employing said people's tactics against their own countrymen. If France were invaded by mongols they would have had no problem quickly learning the local methods of defense and assault and blending the knowledge with that which they already had from a long line of conquests and employing new tools and methodologies right alongside those learned in prior sieges. The mongol horsemen were indeed fierce fighters who made up the bulk of the armies but more often than not a psychological, strategic, and technological edge were how they achieved victory. The real Mongol hordes were a far cry from the simple rampaging primitive berserkers typically depicted by popular culture.

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    $\begingroup$ First, you are not understanding what siege warfare was about. Knocking down walls was never the goal, bombarding the defenders while starving them and breaking them psychologically was how most sieges worked. Additionally, history already proves you wrong as the mongols spent over 2 centuries successfully taking heavily fortified cities and fortresses that were above and beyond anything being built in Europe at the time. Additionally the mongols did fight the Europeans in the holy land and repeatedly kicked them out of their castles. $\endgroup$
    – TCAT117
    Aug 28, 2018 at 3:13
  • $\begingroup$ @kingledion you're right about the seige engines and stone walls, but these weapons would have had another purpose; demoralisation. You don't have to wait 6 months to starve out the people inside if you're also lobbing death over their wall. Ultimately it's about letting the punters inside know that the wall isn't going to protect them in the end. (Sorry TCAT, it looks like we were both typing at the same time) $\endgroup$
    – Tim B II
    Aug 28, 2018 at 3:15
  • $\begingroup$ machines and battering rams broke up the walls and towers, the intrepid besieged never stopped throwing wheeled arrows [sic], pots of naphtha, Greek fire, rocket arrows and stones, without giving way. During this time, it rained so extraordinarily that it seemed that the world was to be destroyed and drowned in a second deluge -Siege of Smyrna. Mongols vs European Christians held up in a castle. $\endgroup$
    – TCAT117
    Aug 28, 2018 at 3:19

TCAT117's answer is really good and insightful; I concur, the Mongols would have subjugated a densely populated state in Ukraine just as they did the less densely populated one they found in OTL.

I just want to add a few aspects:

Batu Khan was only nominally in charge

Until 1236, the Mongols only had direct control westward up to the Volga. 1236 is when they mounted an attack on everyone and everything west of it. In 1236 they dealt with the Volga Bulgars and some other forces before turning to the principalities of the Rus in 1237. After destroying various armies, notably that of Vladimir-Suzdal in the battle of the Sit River in 1238, it took them two years to reduce resisting cities and fortresses. They took Kiev in 1240 and pressed on to Hungary and Poland within barely more than a year.

The guy who devised the strategy and led the campaign was Subutai. He had a great deal more experience than the relatively young Batu. A number of other princes also participated, including the future Great Khan Möngke. The commanders struggled to keep the unruly lot under control. While Subutai - not a descendant of Genghis Khan - had limited authority over the princes of Genghis Khan's blood, Batu Khan was part of the problem, not part of the solution. This was potentially a larger problem for the Mongols than any European resistance. Disunity between the descendants of Genghis Khan is also what finally brought down the empire - it split into several parts after the strife during the election of Kublai as Great Khan in 1260.

So if you want to save the Rus, just have the princes spin out of control a bit faster.

Sheer numbers will not help the Rus

The Mongols were quite capable of destroying badly armed and badly trained peasant armies while sustaining minimal losses themselves. Their advantage was not superior numbers and not even to that extent superior technology, but superior organization and logistics. They were able to coordinate actions of armies hundreds of miles apart to a level of detail that was not achieved again before modern times. And they knew everything about their enemies while their enemies knew preciously little about them. When they invaded Georgia and destroyed their crusader army in 1222 for instance they had crosses carried in front of their armies at first to confuse the Georgians. It worked. They also employed all kinds of illustrious figures in their service and spy network including Europeans (like that English knight).

They were also willing and able to commit genocide and murder a significant part of the population. (This is the link you already gave in the comment to the other answer). In fact, it has been suggested that they assigned little value to agricultural work, viewed farming populations as inferior and intended to convert large chunks of farmland (in China and probably everywhere else) to pastures for their own nomadic groups. Marshall's popular history book makes this point. While this is not a scholarly work, it would definitely explain what happened in Ukraine. The wikipedia article about Subutai seems to concur, citing another book that I am not familiar with as a source.

As a consequence, if this assessment is correct, and they would hypothetically have taken France, they would have murdered just enough of its 18 million inhabitants to make space for the pastures of a Mongol ruling class.

The Mongols were happy to keep local rulers in charge of vassal states

They did that in the case of the Russian principalities and the states in the Caucasus mountains, Bulgaria, Vietnam, and a number of other states. It is unlikely that they would have taken direct control of all of Western Europe, had they ever conquered it. There are few places in the world where their modus operandi would have worked quite as well as here - accepting some minor rulers as vassals while taking overall control and direct control of the important areas. The one thing that would have stopped Europeans from cooperating with the Mongols would have been the pope declaring a crusade against them. And while this was considered, the pope himself could also not quite resist working together with the Mongols.

The Mongols did return and raid again after 1242

They regularly fought small scale wars against various Russian princes and continued to invade other European states, e.g. Poland again in 1259. You are right that Batu Khan did not return, he was dead by then.

China also had stone fortifications

Although I do not think TCAT117's example of the siege of Smyrna counts because it happened a full 150 years after the invasion of Europe in 1241, I still think TCAT117 has a point. Europe may have had the highest density of stone fortifications in the world, but it is not that Mongols were not familiar with besieging stone fortresses. Consider as a different example the siege of Kaifeng 10 years before the invasion of Europe and conducted by the same commander, Subutai. The military technology employed there was simply out of the league of what contemporary Europeans could have coped with. Also note that Subutai did have this technology available in Europe. He used it to reduce various Hungarian fortresses and notably to clear the archers from the opposite bank of the Soja river in the battle of Mohi.

The success the Hungarians had with stone fortifications was not very impressive. Some cities and forts survived the invasion, yes, but the Mongols were in Hungary for two years, no more, before they returned to their empire to wait out the election of the next Great Khan. With more time, they could probably have reduced or starved out the remaining fortresses.

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    $\begingroup$ I think the best way to sum this up, is the only reason we don't speak Mongolian today is because the Mongolian emperor died, and the vegetal in charge of the Mongolian army returned home to support his claimant to the throne. $\endgroup$
    – Pliny
    Aug 30, 2018 at 4:15
  • $\begingroup$ @GarretGang A very pointed assessment. But I have to disagree on the details. 1. Russia was under Mongolian suzerainty for 200+ years, 1237-1480 but Mongolian had very little influence on Russian and only a tiny minority of the Russian population speak Tatar. 2. What put a stop to Mongol expansion was ultimately their failure to efficiently transition from a tribal group to an empire. Had they done that, they would have been back in Europe within a few years. Had they disintegrated earlier, they would never have arrived in Europe. $\endgroup$
    – Solar Bear
    Aug 30, 2018 at 12:43

French could not have stopped the Mongols. The Mongols at their peak were efficient hunters, they hunted armies (trained, high morale, veteran armies). Their aim was to break the armed might of the World and they could have achieved Europe much easier than the East.

Their tools ranged from extreme terror to the best warcraft of a hundred conquered nations and their methods were the best available. They actually moved so fast that they outran news of their coming quite often. They mowed down armies (even larger ones) so quickly that there was no time to get ready for lengthy sieges and with your armed forces wiped out a siege defense is pretty weak and utterly demoralised. And they don't give up, they tasked generals with an objective and that guy doesn't stop however long it takes.

They had expert siege technicians, but siege warfare was a last resort, what they really want is for the fighters to take them on so they can kill them. And the examples they made of lost sieges was absolutely terrifying if you're not looking at it from behind a keyboard.


You do not really need to storm each castle. You can just siege them, and go loot the countryside. Mongol horses need lots of food.

If they decide to storm, they do not need to break the walls. can use fire arrows and catapults to wreak havoc inside the walls.

Once a castle falls, Mongols would brutally torture its defenders, then let the word spread, to encourage other castles to surrender. If they surrender peaceably, let them live, levy a tax on them, just as they did in Eastern Europe.

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    $\begingroup$ "If they surrender peaceably, let them live, levy a tax on them, just as they did in Eastern Europe." Actually, the Mongols killed about half the population of Hungary and Kievan Rus. Also, you can't take fortified places by looting the countryside, see the 100 years war in France for plenty of examples. $\endgroup$
    – kingledion
    Aug 28, 2018 at 3:20

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