So I basically have a medieval fantasy world, where there are several empires on an Earthlike planet. These empires originated from early Bronze Age civilizations, and have stood the test of time in one form or another. Now they are all more or less in the "medieval" era, technologically speaking. And yet socially, these empires are more like medieval China, medieval India, or the ancient Roman empire, or the 19th century Russian empire, rather than medieval European kingdoms. Meaning that they have a standing army, established beurocracy, and they are comparatively as large as the above mentioned empires, having a similar, if not greater level of manpower.

They may be a little bit more advanced than our medieval world, having invented mass production of plate armor and weapons, like a little industrial revolution of sorts. They also have a light magic system, which is primarily used for healing, hypnosis, paralysis, hallucination, mind reading, brainwashing, emotional manipulation, and enhancing mental and physical abilities for some amount of time. Boat technology is retarded however, having only ships like galleys and triremes. Despite this, the entire planet has been mapped out by now, and these empires know that they live on a globe, and they know where all the continents and straits are. However there is no gunpowder in this world.

The entire planet is divided up into six big empires, and numerous smaller kingdoms which are vassals or dependent states of each of these empires. Tensions have been building up over the past century, empires have been making alliances and enemies, two roughly equal sides, three empires and their vassals vs the other three empires and their vassals. Finally war breaks out over border disputes and past grievances.

My question is: what is the feasibility of a world war happening between these empires, on the scale of WW1 or WW2? I mean, armies roughly of that size, but armed with medieval weapons and war elephants instead of tanks. Most of the battles will be fought on land, but some of them will be fought at sea, and of course large numbers of troops will need to be transported to other continents, for the first time in history. What would happen in such a scenario? Even if the rulers of these empires want to wipe their opponents off the map, Hitler style, would they be able to do it?

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    $\begingroup$ There were some big wars in days past. The Arab conquest swept over a huge area. Alexander made it all the way from Greece to India. Mongols warred their way from China to India and the Mediterranean. They were good at wiping out whole cities too; pyramids of heads and all that. Your world can have all that stuff too if it engages your readers or players. Why not? $\endgroup$
    – Willk
    Commented Nov 9, 2022 at 22:50
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    $\begingroup$ And I'm 100% sure the question "what would happen in such a scenario?" is too broad, violating the book rule. Do you have a specific problem? We won't write your story for you. $\endgroup$
    – JBH
    Commented Nov 9, 2022 at 23:26
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    $\begingroup$ I see multiple questions, you should be limiting it to one question. As per this stacks rules $\endgroup$ Commented Nov 9, 2022 at 23:27
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    $\begingroup$ @JBH feasible := possible to do easily. Pretty sure its being used as defined in at last one dictionary. I believe the general question is world building, In terms of they have laid out a (sketched))world and are asking if a particular scenario is plausible. It does need to be reworded to one question that is not asking for a book length answer. $\endgroup$ Commented Nov 9, 2022 at 23:36
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    $\begingroup$ "What would happen in such scenario" is highly dependent on the individuals and individual events, it's so chaotic it's going to be hard to answer reliably without using a lot of "story" elements. Also world wars have been the main topic of a lot of historical and alternative history stories, it's therefore a bite a bit too big for a single question, even alone :|. [...] $\endgroup$ Commented Nov 10, 2022 at 0:15

8 Answers 8


I believe that in practice one might find that world wars, and total war generally, were only made possible by two concurrent but distinct developments, and how these factor in to the 1) capability, and 2) motivation of waging a total war.

First, capability. I think it may be argued that civilization-wide total war was only possible because of the tech level. And I don't mean the weapons; I mean the logistics. In the Roman period, dozens of legions could march into the forests of Germany, or an emperor could personally lead a host against the Persians, and these could very easily be matters approaching life-or-death for the whole empire. But the only people who could have any impact on the proceedings once a war had already started were those within a day or two's walk from the front line (or "front point" morelike, being one of the armies' camps). So what if there were thousands of swords being made in Gaul every day? So what if there were bounteous crops on the Nile? The underequipped, starving troops would win or lose months before any serious supply could reach them. This isn't to say that a civilization couldn't undertake and maintain a serious, long term war effort against another. Only that, unless both the production and logistics tech were advanced enough to make them relevant, it wouldn't be likely to take on the shape of a "total" war.

Second, motivation. If you're going to go to total war, you need a society which is willing to endure sacrifice and loss in order to do it. And, in practice, that loss is almost certainly going to be much more than any loot the country would take in from a victory (as if the average citizen would see any of that, anyways). Why should the peasant in Iberia pay more taxes, work harder, go off to war, just to annihilate a group of people that are a lot more like him than his own rulers that are making him do it? This requires an ideology; a sense of "us" as well as "them", and a belief that wiping "them" out (or at stopping them wiping us out) is worth the massive sacrifices a total war entails. Even back in the professional army period of the Roman empire, it wasn't patriotism that motivated the legions: it was the premise of getting pay, getting privileges, getting citizenship, loot, and land. When these things dried up, so did the legion's mettle. Europe could do total war because it had the idea of the nation. And it wasn't really until the invention of the printing press that national identity started to form amongst the average people.

So what would give your medieval people the drive to maintain a massive drain on their lives, persons, and pocketbooks? Especially when the "world war" in question would actually seem to be 4 or 5 distinct "worlds" away? These are questions for you to answer, but I think they're more or less mandatory.


Maybe. Geography will matter

Rome could never have waged war on China, or vice versa, because of the distances involved.

This is greatly exacerbated by your world's bad naval technology. Triremes were not suitable for crossing large oceans, let alone waging war across them.

If geographical barriers are sufficient, war will be totally infeasible; if lessened a little bit, you'll have stalemates, as supply lines on offence become unmanagable.


  • A) Rome v Australia (forget it)
  • B) Rome v China
  • C) Rome v Persia (stalemate)
  • D) Rome v Britain
  • E) Rome v Greece. (inevitable).

Maybe someone can compute how many days travel the Mongol Empire was; that represents the absolute best a completely equestrian medieval society can do travelling across (admittedly quite hostile) plains.

Ultimately, you need a map so that travel times can be ascertained.


It is possible but the devil is in the details. It would depend on how widespread the war was and what the layout of the world was geographically and politically as not even the Second World War involved every country. Large parts of South America and central Africa were not at war during this period (with some exceptions).

But given the right collection of hostile nations in close enough proximity then very large, protracted and destructive wars would be possible. Case in point the Thirty years war that ravaged Central Europe between 1618 and 1648 with millions of dead https://en.wikipedia.org/wiki/Thirty_Years%27_War

This is a little after the traditional medieval period, but it was suggested that technology had increased beyond medieval levels anyway and technology was not advancing at a vast rate then.

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    $\begingroup$ The Thirty Years War is what killed the feudal world dead. It began in an Europe which was not very different from the late Middle Ages, and when it ended, the Modern Age was born. And yes, it was a full dress rehearsals for a World War; in addition to the European theater there were secondary theaters in the Americas and in Africa. $\endgroup$
    – AlexP
    Commented Nov 10, 2022 at 8:26

Geography wise, it's probably theoretically possible, but the bigger question is why.

But lets address it on two fronts, using ww1 as our example, because WW2 was almost directly as a result of WW1.


Although The Great War was a world war, it wasn't necessarily like it was continuously fought all across the place by everyone all the time, it was more that it was two large groups allied together fighting on multiple global fronts. So the bulk of your trench fighting is in continental Europe sure, predominantly in France, Belgium and to a lesser extent Germany, but there's a whole other front in Russia, there's stuff going on in Italy and in this war, Japan are part of the Entente or allied powers, but in the next one they've switched sides. But most of what's happening here is, relatively speaking, pretty local.

Gavrillo Princip assassinates the Austro-Hungarian Arch Duke Franz Ferdinand, and he's Serbian, so in response, Austria-Hungary invade Serbia. Serbia has an alliance with Montenegro so they drag Montenegro into the fight. So far, so small. But then, this is where the alliances start coming in, because Austria-Hungary, German and Italy have an alliance. So German troops, supporting their pals in Austria Hungary get invovled and march into Belgium and Luxembourg, but these countries were declared Neutral, because this is very much a time of empire and the big empire having countries didn't want to fight amongst themselves all the time when they could be off doing terrible things in far off lands. So now you have your other Alliance coming into play, because The UK, France, and Russia have a treaty to protect the Neutrality of Belgium, and now its time to uphold that.

And for a long time geographically speaking, this is where it's all happening. It's in the fields in france, and it's people who are being ferried over to do it.

You're sort of past the age of sea battling by WW1, but when there were some, they were being conducted in small areas like the channel (or La Manse if you prefer). Certainly if you go back towards the reign of Elizabeth the 1st, thats where sea battles with this sort of ship technology were happening. The crucial thing here is that you've got friendly forces making a big land corridor, or a small sea corridor. If Russia needed to go all the way to Italy to do its fighting with no promise of food and supplies? They'd have issues!

Why though?

Politically speaking, this might be relatively easy to answer. WW1 started because of a land grab in the break up of the Ottoman Empire, WW2 started because Germany felt, perhaps quite fairly, that they were done very badly by in the wake of WW1. Your kingdoms might simply want more power or more space. For example the current Russia Ukraine War, or an aggressor might attack for religious reasons (The war in Afghanistan and Iraq).

What's harder to answer is the "why" for the every day person. Why do they want to become soldiers or go off to war or make munitions or buy war bonds?

Again, you can look to history for your answers. The Spartans have a culture of war. You go off to war and you come back with your shield or on it. So victorious or one of the glorious dead. The entire culture lives and breathes this, and so it's perfectly possible to imagine a massive spartan empire declaring all our war because to Spartans, war is the entire point of life.

The Greeks you have this idea of societal taxes, you earn enough money and there's no question, you're fitting out war ships or you're fitting out choruses for the next play. One or the other.

Certainly a common thread for why people become soldiers throughout history has a lot less to do with any kind of civic pride and a lot more to do with being paid well, fed moderately and housed mostly. Especially if you're looking at a medieval style fantasy era, the promise of regular meals might well be enough to build an army with, they won't necessarily give two hoots as to who they're fighting or why, so long as they get paid afterwards.

Or you can engender some degree of national pride, combined with a fear of what will happen to their loved ones. The "Your Country Needs You" posters, if you don't fight off these aggressors they'll invade your homeland and do terrible things to your women and children.

Often I suspect its a bit of both. Keep the other guys out, get paid, try not to die yourself.

So, those are the questions you need to answer. Why are they fighting, whats the end goal, and does the geography allow for it?


Being generous, at most something on the scale of WW1

Whilst other answers address some important considerations with geography, there is something that is being heavily overlooked. Logistics

Perhaps the single greatest thing that contributed to the scale and brutality of both World Wars wasn't any weapon, rather it was industry.

The industrial revolution brought with it many changes that greatly changed warfare in general. On the more technical level, more advanced metallurgy, higher quality smaller parts that could be made on mass. Increased production of traditionally expensive weaponry, better ships/hulls, better clothing etc.

Scale and quality greatly improved. Whilst you have no gunpowder in your setting, you still have to answer to the scale question.

The industrial revolution not only improved quality but churned out numerous pieces of items at a much larger and faster rate than ever before. The advent of better machinery and tools had also meant that labor and manpower hour for production were sharply cut down. Equally important, it also standardized the quality of equipment.

The mass production of military equipment had meant that warfare took a more deadly and wider scope. One of the first modern wars, the American Civil War, was particularly brutal due to better weaponry that was produced on mass. The quality of a musket or rifle wasn't dependent on the skills of a certain blacksmith. Rather the tools and quality control of a factory. This means that both sides, but especially the North, could field large armies very quickly. The training needed to fire off a musket or rifle was significantly smaller than that of a spear or sword. It takes less time to make a soldier proficient with a firearm compared to that of knights, bowmen, calvary, siege engine crews etc.

However, you want something on the scale of World War 1 at least. By now the industrial revolution has more than matured and left its mark. The scale of industry is far larger than compared to the mid 1800s. Rifles, artillery, bullets and artillery shells are produced at an incredibly large level but in a short time as well. HMS Dreadnought set off an arms race for the ocean as engine, artillery, and metal technology saw massive gains compared to the days of early ironclads. This technology percolated throughout the rest of the military and rest of society.

Staying with the first World War, some of the things that made it so deadly and large in scale were:

  1. Access to firearms that can be quickly and easily trained with. Deadlier ammunition that could be created on mass. Conscript armies that are of higher quality than any peasant conscript army with the ability to inflict far more damage.
  2. Large scale production of artillery and ammunition
  3. Better engines
  4. Armored ocean going vessels capable of holding significant weight and weapons.
  5. Transportation ships that could haul far more in goods and much faster. So much so, that the United States and Canada could heavily support the United Kingdom in both wars, as well as the Soviets during the WW2
  6. Better clothing for adverse environments
  7. Factories with the ability to change production and address deficiencies in certain areas (see Shell Crisis of 1915).
  8. Long and better range communications. Radios changed warfare greatly.
  9. Better medicine as well as hospitals. Combat medics and surgery for injured soldiers were far more intensive than compared to previous wars.
  10. Increased attention to media, literacy and education. With the power of nation states having increased so greatly by now, the idea of a national spirit/unity cannot be understated. Technology, improved literacy and propaganda allowed people to reach a much larger audience.
  11. Railways/trains. It cannot be understated how important rail was for
    both World Wars. Not only did they move soldiers to a frontline in the event of mobilization, but they greatly aided in transportation of equipment from factories to the front line.

Plus, many more.

However, your fantasy setting has some roadblocks in the way of getting a true WW1 or WW2 scale. Even with a light industrial revolution.

For example, the lack of ocean shipping means that logistical support over ocean or force projection is basically impossible across water bodies. You simply don't have the sea faring capabilities to sustain an invasion across an ocean or a large water body. You won't be doing any island hopping, massive multi front amphibious assaults (Operation Overlord + Operation Dragoon). Supporting allied factions across a body of water in a meaningful way on the likes of WW1 is going to be very hard if not impossible. Whilst a land army can march (Grant+Sherman and the Romans for example), they're going to either have to rely on the land or strain their logistics heavily. If you don't have food preservation technique on an industrial scale, you have an even larger problem (especially for war elephants). Your army runs the risk of starving out if any defending and retreating faction employs a scorched earth policy if your invading force scavenges for food.

Combat Losses- Replacing combat losses is going to be much harder than say WW1. Even if we are being generous and mass arming your soldiers with crossbows capable of piercing plate armor reliably and spears, both still require a decent amount of training to become battlefield proficient. Every soldier that you lose, especially veterans, is going to heavily impact your army. Reinforcements are going to take a lot longer to come up to speed and perform cohesively. A faction runs the risk of being steam rolled should they sustain either mass or even key combat losses. You have no artillery to equalize or force multiply. You can't just spend a few weeks training a conscript how to use a crossbow or spear and then ship them off to the equivalent of Gallipoli or Verdun.

The mass casualty combat events on a scale of WW1, even worse WW2, isn't going to be sustainable for both your army and your industrial system.

Industrial production- The lack of things like gunpowder and advanced industrial mining means that getting ores and metal is going to be a costly and time consuming process. Especially on short notice. The machinery brought on by the industrial revolution by the turn of the 20th century greatly allowed nations to quickly mine and produce goods and equipment. Complex networks existed to supply factories.

Fortifications- Forts are going to prove to be far more deadly than that of WW2. WW2 introduced the concept of large-scale maneuver warfare. Forts could be bypassed, left to be dealt with at a later day. While both the Allied and Axis forces did fight battles over forts, they didn't pose the same power as pre cannon days. The invention of bombardment types of weaponry gave rise to an entirely different type of siege warfare that your forces don't have access to. Forts and trench lines in WW1 proved to be a difficult task to break through, tanks helped alleviate some of the issues. Heavy artillery helped as well. However, your fantasy army will have to deal with them. Starving them out takes time and requires a contingent of soldiers to watch over them. Taking a fort by force is going to be costly, even if you have a lot of siege weapons. This is going to break up your force concentration ability. Sieges also take a toll on both factions' logistics. Whilst this may appear to make a static frontline like WW1, you are going to lack the force maneuvering that WW2 saw. Theater wide scale will be brought down; however, you will now have an established frontline.

Transportation- The lack of trains and rails means that you can't transport troops and equipment quickly across long distances. You also won't be able to quickly redirect reinforcements or resupply a frontline. Every horse, or pack animal, that you lose, is significantly hurting your ability to wage a world war. Living animals take time to grow. Yes, ancient and pre modern armies marched and supplied themselves on foot. However, their scope of conflict didn't have the same breath/width of combat that WW1 and WW2 experienced at the same time across fronts.

Electric Communications- Whilst large land campaigns have been conducted without the use of electronic communications, both WW1 and WW2 heavily benefited from things like wire and radio communications. Whilst soldiers in WW1 didn't have personnel radios like now. Larger armies, generals and nations had the ability to quickly communicate with each other. For your fantasy setting, your central headquarters is going to have some issues in getting information about the frontline, who is maneuvering where, and creating a composite image of enemy force concentrations and dispersion. Even if you leveraged your magic system for tradecraft, it still is going to take time for that information to reach someone, and for an action to be taken in response.

So how do you get something near World War 1? As others have stated, geography. Each faction has to be close enough in that they can quickly bring reinforcements and equipment to the frontline. With little space in between, invasions are more easily to be sustained. Your light industrial revolution has also caused the explosion of maintained roads. These roads will be the closest thing to rail you can get. Because of the close proximity of sorts, a cold war of sorts has been developing. So, your standing army also has significant reserves back home. Even better if something like a national guard or home guard exists. World War 1 was mainly fought in Europe and adjacent regions. There was no island hoping, daylight bombing raids on the scale of the Second World War, maneuver warfare using mechanized forces like Operation Cobra or Arracourt. After the initial German breakthrough buckled and slowed by Paris, trench warfare and stalemates started to become more of the norm. You can replicate this through the use of fortification lines with numerous forts. Each fort should have enough resources to sustain a siege and supply and reinforce another fort in danger.

Lastly some perspective. The Thirty Year War claimed some 4.5-8 million soldiers. Germany fielded an army around the size of 3 million in just the invasion of the Soviet Union during Operation Barbarossa. The Soviets would lose about 4.5 million soldiers during said invasion.


Since apparently you want it to be possible, there are two major factors you have to work out.
First, an army marches on it's stomach. That means, unless you can sustain your troops for the entire duration of the war, you won't be able to win it.
While that does include weapons and armor, the bulk is food and fodder. To get that to the troops, you should have either a very good road network and excellent logistics, or you might even consider a railway network, maybe horse- or ox-driven. Still, it is an enormous endeavor, and you may need to involve quite some magic to pull that off without steam or combustion engines.
Thinking about it: Sail-driven railway would surely look really cool...

The second aspect is information.
In order to get your armies to march in the first place, they need to be informed that they are to march, and where to. They also need to report their progress, casualties, needs, intelligence, and whatnot. Communication is absolutely necessary both for tactics and for the coordination of logistics.
Fast flow of information is also necessary to levy troops and to get the population to support the war. Again, with magic you can have telepaths do hat job, or magic devices that enable long-distance communication. On the side: unless you have high levels of literacy, neither will you have very efficient propaganda, nor will the opposition be able to print pamphlets.

What you won't have, however, is the level of destruction and devastation that our world wars brought. With mostly melee, catapuls, (cross -)bows and such, you can never cause the same amount of destruction as explosives do.

So yes, if you really want that you can have a world war in your settings. You should still have to think of a reason why your nations should want that, and it will look and feel a lot different than our world wars did. Also, keep in mind that your army is taken from the workforce, so you should find some kind of explanation how you are still producing enough food for everyone.


If magic enhances food production

You mentioned that you have physical enhancements from magic. If they also enhance crop production then you can have a world war.

The main limitation on moving armies was food and clothing. Food runs out, shoes wear out, and you can't move them any further. With effectively infinite food, moving huge armies is no longer an issue.

This also makes mounted infantry a lot further ranging. The main reason tanks and trucks replaced horses was because petrol is very easy to transport, energy dense, and allows much faster movement. If your horses have unlimited food then they can act like trucks.


While a bit late for your timeline, The Seven Years War was a global conflict that started in Europe between the alliances of England, Prussia, and Portugal, vs. Spain, France, and Russia and Austria. Mixed in were several minor German powers which either directly fought with major power allies or sold mercenary services. The war had theaters opened in Europe, North and South America, and Asia.

The U.S. Revolutionary War, saw the American Colonies allies primarily in France (Because in the late 18th century, it's more surprising if the British Empire is at war and France isn't involved) but also Spain and The Dutch Republic face off against British and German allied Mercenaries. It wasn't on the scale of the 7 Years war, but was a direct consequence.

You also have the Napoleonic Wars which was a series of wars that was France vs. all of the rest of Europe (At the greatest extent of the France's control, Continental Europe was under France's control with exception to Portugal, Wallachia, Moldavia, Russia, and the European parts of the Ottoman Empire. Additionally, the British Islands, Sicily, and Sardinia were also out of Napoleon's control). The Napoleonic wars would also serve as the last major conflict in Europe until WWII nearly 100 years later.

As mentioned earlier, the Mongol Empire at it's height Controlled an Empire from the Pacific Coast of Russia, and as far east as Ukraine and much of the Persian Gulf, the largest contiguous empire ever held and largely assembled in Ghengis Khan's life time alone, mostly through war.


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