Technology Level

The planet has a level of technology of about the early 1800's. They have some basic steam transportation, muskets and bayonets, cannons and other basic artillery, and some less developed nations still do use swords, bows, and other more primitive weapons. Many countries still do use horses and other animals and ride on them, because many poorer countries haven't modernized their military.

Goal and Rules


  • stick to the technology given (no nukes, aircraft, etc.)
  • you may use genocide, but war has to be the main cause of death; genocide can only be secondary. When you use genocide, try to explain the mechanisms of how the people are killed and etc.
  • you can have events prior to the war do some damage but they don't count as part of the kill count. As an example, you may use an economic depression to motivate some sort of genocide.
  • Edit: you can use disease and famine as after-results from the war.

Question: Is it even possible to have a billion people dead in a 17 year war with this level of technology? I feel that this isn't possible and I am overreaching a lot, but I'm open to your ideas.

Edit: The population is like about 2 billion.

  • $\begingroup$ Comments have been moved to chat; please do not continue the discussion here. Before posting a comment below this one, please review the purposes of comments. Comments that do not request clarification or suggest improvements usually belong as an answer, on Worldbuilding Meta, or in Worldbuilding Chat. Comments continuing discussion may be removed. $\endgroup$
    – L.Dutch
    Commented Oct 7, 2023 at 20:44

10 Answers 10


According to the estimates I have seen, what you ask is not possible, for the simple reason that a 1800 level tech society barely supports something less than 1 billion people.

A war which is fought with the means available in that time, requiring close range interaction to kill, would stop by self exhaustion before everybody is killed. It would likely bring with some epidemic like cholera or the plague, which would help killing a lot of people, but would not lead to the complete wipe out.

  • $\begingroup$ Thank you, that is what I thought. $\endgroup$
    – Neil Iyer
    Commented Oct 5, 2023 at 2:48
  • 12
    $\begingroup$ @NeilIyer your "the main reason must be war" restriction is the main problem. Even in literal wars the main cause of death almost always was NOT combat action (or similar "war stuff" but diseases in the camps, lack of food, extreme weather or similar. $\endgroup$
    – Hobbamok
    Commented Oct 5, 2023 at 13:55
  • $\begingroup$ @Hobbamok Ok, if I remove that restriction is it fine? $\endgroup$
    – Neil Iyer
    Commented Oct 5, 2023 at 14:33
  • $\begingroup$ @NeilIyer yes, if more of your world is like China/Asia (e.g. suitable to large-scale rice cultivation). Why? Because rice sustains far more people per area than most other grains/crops, increasing the population density => more people to kill. Since it's the 1800's you could make some countries dependant on natural fertilizer (bird poop, read up on it), in which case a mere disruption in their guano source could kill billions (some in the resulting civil war if that counts) rather easily $\endgroup$
    – Hobbamok
    Commented Oct 5, 2023 at 15:15
  • $\begingroup$ In support of this answer, a world population chart suggests that in the year 1800 there were only 1B people on the planet (100% fatalities during war world-wide) to about 1.7B people in 1900 (~60% fatalities world-wide). WW I's total estimated deaths was only 40M. I could believe engineering an 1800s war that killed 200M, but that's my upper limit. $\endgroup$
    – JBH
    Commented Oct 5, 2023 at 15:51

Running an estimate:

  • The 30 Years' War ran approximately 30 years and killed about half the population in the affected area. But not every day had the same intensity of fighting.
  • The war caused mass civilian death through military requisition of supplies, disruption of food production, and pandemics running through vulnerable populations.
    Basically, agriculture of the 1600s was barely keeping up with the hungry population, and the same would apply to a somewhat larger population in the 1800s (see the influence of famine on the French Revolution). That's an average, there were good years and bad years. If an army marches through and steals food, fodder, and animals, it tips into famine.
  • Death rates are sometimes estimated by before-and-after comparisons, but an entire generation would have been born during those 30 years. So before-and-after underestimates the death toll. On the other hand, 30 years would have plenty of natural deaths.
  • The side with railways has significant advantages in their supply, of course. Instead of sending half their troops foraging for food and fodder, and the other half escorting the foragers, the railway-enabled side can have half the troops rest and the other half ambush enemy foragers. As long as their own camps are within practical marching distance of a railhead.
    • Where does the food come from?
      "Delivered by the railway, don't know from where" says the cavalry trooper who has escorted plenty of oxwagons.
      "From the supply hub behind the front," says the colonel.
      "From this and that farming province hundreds of miles away," says the quartermaster who has looked at the freight manifests.
      If those farm areas have friendly populations, they will be taxed to support the war effort. The tax collectors won't deliberately cause famine and mass death, but they will cut to the margins. If the rains come too early, or too late, on top of that, people may die. And if the farm areas have hostile populations, tax collectors may see starvation as a side benefit. Either way, tax collectors may assume that farmers hide half of their crops anyway, and demand the delivery of all of the rest.
    • The side without railways would have incentives to wreck them, and also productive areas far behind the front. If populations have become dependent on railways (e.g. industrial towns without enough farms of their own), they will starve.
    • Rounding up forced labor to build/extend railways could become another source of death. Probably the German V2 missile killed more slave labor than Londoners (yes, different technology, I mean the principle of ruthless leaders 'expending' human lives).

It seems entirely plausible that your fictional war kills half or three quarters of your population in a dozen years. Just mix plundering armies (especially unpaid mercenaries) and a bitter hostility between different sides.

As others pointed out, the problem is to have so many people that half or three quarters of them come to the required number. Make your agriculture in many areas both reasonably effective, and dependent on irrigation canals. Then have the different factions destroy canals and locks, and plenty of food (allowing a large population) suddenly becomes a breakdown of food supplies which cannot be made up by the next harvest season.

  • 3
    $\begingroup$ Where does the food come from? "From a farm," says the cavalry trooper who grew up on a farm. Rural people are more likely to know horses - and more people are rural in an early 1800s society. $\endgroup$
    – Jedediah
    Commented Oct 5, 2023 at 10:49
  • 1
    $\begingroup$ @Jedediah, I was assuming that this trooper knew the food was not from a local farm. $\endgroup$
    – o.m.
    Commented Oct 5, 2023 at 15:04

If we look back into history, disease and starvation are pretty much universally the biggest killers.

So, in your world, create a scenario which causes mass starvation. Disease is likely to follow and do its thing with the weakened survivors.

  • $\begingroup$ War generally pushes people away from their farms which causes mass starvation. See the recent population movement from Nagorno-Karabakh and think just how all those people are going to find food and shelter in a new location. $\endgroup$
    – David R
    Commented Oct 5, 2023 at 14:29
  • $\begingroup$ Stop burying your dead and three quarters of the population dies from the plague. $\endgroup$
    – Mazura
    Commented Oct 5, 2023 at 23:57
  • $\begingroup$ I think travell movements by animals can be great disease vectors. So its basically - bread a bio weapon that also attacks crops and then unleash a migrating swarm. After that watch society fail. $\endgroup$
    – Pica
    Commented Oct 9, 2023 at 10:49

The thing that comes to (my) mind would be biological warfare that got out of hand.

An infectuous disease, or an insect pest, that gets weaponized (hey, animal husbandry has been a thing way longer than the 1800's) and "succeeds" beyond expectations.

It needs to be something self-multiplying to reach so large a part of the population. And it needs to be "out of hand" given the restrictions of your question: "Half the population" means a significant amount of non-combattants were killed, and that without genocide being a primary goal of the war.

Since the "disease" thing has been ridden to death already (no pun intended) and requires a working knowledge of the germ theory, which happened rather late in earth's history, I'd go for the insect angle. Something that was intended to have a limited spread and e.g. not survive the winter, but did survive and multiplied far beyond expectations. There are a lot of options here.

A new breed of locusts, leading to wide-spread famine (intended to kill only one crop in the target area(s) to force an armistice).

An unsually aggressive breed of mosquitos native to the planet that cause severe afflictions (e.g. seizures or other neurological disorders, boils that get secondary infections etc.), intended to only affect troops in the field.

Some kind of parasite with all kinds of unsavory effects on the body.

Depending on what your main storyline is to be, that threat could still be very much present at the time the story takes place, be completely erradicated (but not soon enough to save all those people), or just a somewhat-mitigated background buzz to help with the impression of "alien planet" and "oh yes, that happened...". It could have been erradicated / mitigated by human interference like hygiene / protective measures, or by natural causes like an extremely cold winter / natural predators migrating to new feeding grounds etc.

  • 1
    $\begingroup$ "and requires a working knowledge of the germ theory" not really. The conquistadors used biological warfare on the native population of North America without any sort of modern germ theory. The natives were purposefully given blankets and other things that were in contact with smallpox. Which then quickly infected the native population as it had very little resistance to this foreign disease. $\endgroup$
    – VLAZ
    Commented Oct 6, 2023 at 10:28
  • 1
    $\begingroup$ @VLAZ The effectiveness of that incident is being disputed, as smallpox was already rampant among the natives at that point. This also was attempted genocide, not a (side-) effect of war. Plus: Organized, symmetric, high-casualty warfare like described by the OP pretty much implies established common borders (because oversea projection to an isolated population would be rather poor, as would be the reason for high-intensity warfare). All in all, I don't think that event to be that similar to what I discuss in my answer - and also somewhat distastefully close to potential real-earth victims. $\endgroup$
    – DevSolar
    Commented Oct 6, 2023 at 12:09

This may be doable

While the OP ruled out Genocide, he did not expressly forbid Democide. Throughout history, total warfare has been practiced by various civilizations not to ethnically cleanse an enemy, but to kill each and every member of an opposing civilization regardless of thier race, gender, age, etc. Such wars are even more deadly than genocide because literally no one from the losing faction is intentionally spared. When you look at societies that favor democide over conquest you see a pattern of warfare where seeing 90% of a region's total population being quickly wiped out is not just possible, but a common occurrence. (There is a reason we don't have a lot of democidal societies left)

So, if a system of democide were to be adopted by a major empire like China or Britain, then it could in theory trigger a chain of democidal wars where each country tries to completely eliminate thier neighbors out of fear of being completely eliminated until ~50% of all people are dead. So, if you were to see democide spread to just over 1/2 of the world's civilizations, then seeing 1/2 of the total human population get wiped out, not in one war, but in a chain reaction of lots of wars, could be believable. Lasty, democide is a matter of culture, not technology. Any country of any level of advancement can do it, it's just a question of spreading this culture.

  • $\begingroup$ "a chain of democidal wars where each country tries to completely eliminate thier neighbors out of fear of being completely eliminated" I'm not following the logics here. Great Britain invades and slaughters France, and in reaction Germany slaughters Poland? How does that help them not being the next victim of GB? $\endgroup$
    – xLeitix
    Commented Oct 6, 2023 at 11:14
  • 1
    $\begingroup$ More like GB slaughters France, Spain steps in and they get slaughtered too; so, by the time Germany and Italy step in, they slaughter GB. Then when Poland decides to conquer Germany following old RoE, they lose, and Germany turns around and slaughters them too (because Germany is a new RoE country now), but then Italy now knows Germany has become too dangerous; so, they invade and slaughter Germany before they can recover. Now everyone is scared as hell of Italy because they just slaughtered 2 nations, and the cycle of fear and extermination continues. $\endgroup$
    – Nosajimiki
    Commented Oct 6, 2023 at 17:41

I'm going to completely disagree with L.Dutch.

I think it is entirely possible... With the right motivations.

Now - a quick caveat here - In the real world - most wars are fought for victory, not total annihilation. I'll get to intentional genocides in a moment.

Firstly - historical population perspective - 1804 is the estimated time when the global population hit 1 Billion people, growing to 2 billion in the early 1900s.

So with 1800s technology, globally, it's possible to support the population needed to kill 1 billion people.

Next up - we have Man's ability to kill his fellow Man. There's a few instances I'll point to - the Native American depopulation (going from an estimated 60 million down to 6 million in 100 years) and the Rwandan Genocide (killing 500,000 in 100 days).

I've picked both of these for a reason - Rwanda happened mostly with Machetes, and the Native Americans were killed by a combination of disease and combat. Granted, both aren't hitting 1 billion people - but I want to add some points here:

Rwanda - this was essentially a tribal conflict (yes, yes - a whole load of historical context is getting glossed over here) - and was just in a single country. In addition - the men and boys were killed, the women were raped. If we the goal is to hit 1 billion, then women and girls get the bullet too.

Native America - there's various views on this - some say that it was intentional biological warfare (which I think is a bit of a stretch, given the understanding of disease in the 1500s) whereas others say it's a combination of factors, including disease, conflict etc.

Next up we have to talk technology - what do we have?

Well, we have the Maxim Machine Gun, we have pre-dreadnought battleships (like the IJN Mikasa), we have large calibre artillery. We don't have chemical warfare and biological warfare is limited to things like hurling dead/diseased bodies at the enemy.

Finally - we need the manpower to do it.

Well, I'm British and I'm going to use the height of the British Empire (400 million people) and I'm going to say that we are going to fight the rest of the world (1.3 billion people) - hold onto your tea, Lads! It's colonizing/genociding time!

400 million people to kill 1 Billion, that's a ratio of 2.5:1 people. Realistically though, we have to factor in that our combatants (fighting age men) are going to be more like 100 Million - so that's 10 to 1 - however, once the opposition's fighting men have been dispatched - the women and children aren't putting up a fight. And the ratio of fighting men to fighting men is probably going to be reasonably consistent - e.g. 2.5:1. Assuming a technological advantage - easily doable.

The key factor though is motivations and prep time. Rwanda had months and months of stockpiling and escalation, Desert Storm (as an example) had about ~6 months of marshalling before the initial invasion. For such a feat, there would need to be some serious preparation time - building and stockpiling of weapons, National Service, building of transport ships (could be done under many guises).

Motivation is that you want to kill everyone and everything. Possible, I mean one look at mid-century Germany - but in the history of warfare, men were killed, women and children were enslaved.

The lack of reliable long-distance communications would be a significant factor, with a bit of luck and the right conditions, the aggressor could mount a lightning assault on an area.

Putting that all together - with the 'right' conditions, here's how it would work:

Britain and her Empire spends the latter part of the 19th century preparing for a mass global genocide, they build up significant arms, weapons, ships - all fighting age men are conscripted and indoctrinated for the upcoming mission.

Firstly - because this is not a military operation, the attacks start with isolated places or places of no strategic significance. This should enable the attackers to be successful and if the target is completely annihilated, no survivors can raise an alarm.

From there, it progresses to larger and larger targets - this is where the other global super-powers (France, Russia, Japan, USA etc. etc.) would start to fight back - the goal of the British here though is not to engage them in open battle, using a tactic of deliberately genociding undefended villages/towns/etc., forcing the remaining populations to flee to the more heavily defended cities.

The goal here is to concentrate and over-populate an area with as many people as possible. Using artillery to pen them in, then either by happenstance or deliberate means, set something of a plague against the defenders - either using corpses or diseased captives hurled at the enemy - letting it take it's course, then once the defenders are weakened - rush in and mop up the survivors.

Such an engagement could be done over the period of 17 years (WW1 and WW2 were over a period of 5 years or so). If done with deliberate and thorough means (e.g. once the 'battle' is over, everyone is systematically murdered), I think it would possible.

Realistically it would end-up that something like 200-300 million people would have been killed as a direct result of combat (bullets, bombs, blades) the rest would be a combination of starvation and disease.

To put into perspective, WW2 has an estimated 50 million deaths as a direct result from war, that's in 5 years, and yes whilst there was modern weaponry (e.g. mass bombing) there was also rules against deliberate genocide and modernish medicine - namely antibiotics. Using WW2 as a benchmark, you could get 200 million dead in 20 years - If we use the historic ratio of 3:1 for wounded to Dead - that's 200 million dead, 600 million wounded. Using 1800s ratio for military hospital survival (40%) - that's another 250 million dead.

Then add in the fact this takes care of most of the enemies fighting age men - the rest (women and children) are essentially just waiting to be slaughtered.

TL;DR With the right prep, the right circumstances, it's within the realm of possibility.

  • 4
    $\begingroup$ The problem with the disease is that it was the introduction of many epidemic diseases to a population with no history of them. These diseases have a history of killing up to half the population on first epidemic, but in order to have that many diseases, you need a reserve population that developed them, lived through the initial epidemics (spaced over centuries), and will not suffer the same harm. $\endgroup$
    – Mary
    Commented Oct 5, 2023 at 12:47
  • 4
    $\begingroup$ I don't understand how Britain holds out in this war against the entire world for almost two decades, nor why you're using WWII death tolls as an estimate for what you can get with 1800s technology. This also just sounds like genocide, Britain's entire purpose in the war is to eradicate the other side. $\endgroup$ Commented Oct 5, 2023 at 13:01
  • $\begingroup$ @NuclearHoagie yeah but OP's "no genocide" statement is so incredibly vague that you can't answer the question respecting it because I have no clue what he even means $\endgroup$
    – Hobbamok
    Commented Oct 5, 2023 at 14:00
  • 3
    $\begingroup$ @Hobbamok In general warfare, killing people is a means to accomplishing some other goal. In genocide, killing people is the goal. The OP means that the intent of the war cannot be wiping out 1 billion people, it must be a side effect of some other goal. $\endgroup$ Commented Oct 5, 2023 at 14:12
  • 1
    $\begingroup$ But where would the motivation come from? The Rwandan genocide was, as you said, a tribal conflict escalated for political reasons, but that kind of war doesn't spread very far between countries. And, while racist ideology fuelled German war efforts, other countries had their own reasons to join WWII, and they had no intention to kill all their opponents to the last woman and child. I can't think of a plausible way of combining fanatic killing with a (nearly) global war. $\endgroup$
    – Cloudberry
    Commented Oct 5, 2023 at 19:10

Not sure if I saw this mentioned, but there's of course the issue of life-expectancy in the 1800's. War technology or not, the 17 year war you describe is approximately 1/3 to 1/2 of the life expectancy of an abled bodied fighting individual back in the 1800s. So basically, once you turn 18, you go to war, and war will eventually become your "mid-life" crisis. And 17 years is an awful long time to ask of someone.

War has historically has always been a big baby-boom, but I'm not sure the population would support the military force required to pull this off... mostly because it's really easy to extrapolate the numbers of at least one of the wars.

But if you consider the "War of 1812" (the war is largely considered "inconclusive" by the way.... although the US did get Florida from it!):

United States: Up to 15,000 deaths from all causes[5][4]

United Kingdom: 10,000 died from all causes[1][b]

Indigenous allies: 10,000 dead from all causes (warriors and civilians)[1][c]

Spain: <20 casualties

We'll round UP and call it 35,000 deaths from all sides (and that's a generous statistic btw), and that war lasted just over 2.5 years which equates to about 14,000 deaths/year.

Extrapolating the numbers a bit: 1,000,000,000 deaths ÷ 14,000 deaths/year = 71428.571 years (give or take).

Source: https://www.battlefields.org/learn/articles/war-of-1812-faqs#How%20many%20people%20died%20in%20the%20War%20of%201812?

The other issue is travel:

There were no airplanes. The trek from England to the US by boat during that time, takes anywhere between 3 and 6 weeks... and they would need on (estimated) average 10-20 ships assuming assuming 500-1000 soldiers per ship. That's assuming they managed to actually make it to land... The real challenge back then was playing games like "Dodge the Scurvy" or "Marco, Polo? Sorry, I thought you said Cholera!"

So, really, to do it in 17 years is impossible simply because with the very personnel required to fight in-person, it would be near impossible to physically get the numbers required to kill that amount of people.

BTW, the estimated world population 1800 was around 1 billion, and by 1900 it went up to 1.6 billion.

Source: Google

I did ask ChatGPT to figure out some numbers and there is one possibility to meet it, but very unlikely:

Cause of Death Estimated Deaths/Year Duration (Years) Could Reach 1 Billion in 17 Years? Additional Years Needed
Cholera ~30,000-50,000 Intermittent outbreaks No Thousands
Tuberculosis ~500,000-1,000,000 Ongoing No Hundreds
Yellow Fever & Malaria ~100,000-500,000 Ongoing No Hundreds to Thousands
Smallpox ~300,000-500,000 Varied No Hundreds
Great Famine (Ireland) ~125,000-250,000 7 No Thousands
Napoleonic Wars ~300,000-500,000 12 No Hundreds
Taiping Rebellion ~2,000,000-3,000,000 14 Yes (if we consider the higher end) -
American Civil War ~120,000-150,000 4 No Thousands
Industrial Accidents & Pollution ~10,000-50,000 Ongoing No Tens of Thousands
Colonialism & Imperialism ~50,000-200,000 Varied No Hundreds to Thousands
Natural Disasters ~10,000-100,000 Varied No Tens of Thousands

Your best bet would be to ask China how they did it? :)


I think it's possible--and doesn't even need to be intentional. Let's look at Earth's history--we have a truly devastating but slow killer: HIV. It appears to have arisen at the end of your time window, but that's purely chance, there is no reason it couldn't have made the zoonotic jump before then.

While mosquitoes don't spread HIV let's suppose this disease can be spread that way--but it's in an isolated community with a climate unfriendly to mosquitoes. The war brings it out into the world.

Yes, it would have happened someday, but back then there would be no hope of finding a treatment in time--everyone who is not immune will die over the next years.


Biological warfare, including so-called gain of function, can be done with 1800s (or earlier) technology. For example, passing a respiratory disease between nearby cages of ferrets (or enemy prisoners) through a number of generations (of the disease) can strengthen the disease and its infectiousness. Hardly a good approach if it’s not specific to the enemy though. Your guys are going to die eventually too.

I think I would use an animal or plant disease that would wipe out the other side’s food supply, thus crippling their military and, perhaps incidentally, decimating their population. This would work if there were religious, climactic or other reasons that the enemy was particularly dependent on a single foodstuff, so something like potato blight or African swine flu could quickly and effectively destroy the majority of their food supply. There is a bit of a plausibility issue here in that a billion enemy people would not normally be living in similar climactic conditions, but perhaps that can be overcome.

From early in the 20th century we can find examples of proposed or implemented attempts at this such as Operation Mongoose and the alleged US use of biowarfare during the Korean War (a lengthy report on the latter can be found online- tying it to the infamous Japanese Unit 731). Whether those are true or not, they should provide a good source of inspiration.


The right motivation

As others pointed out, war for political reasons would most likely "burn out" before half the population is gone. However there is one reason in particular, which could cause an all out war, where no one is spared and everybody will go into the fight: Drastic loss of space.

In the event of a sudden and extrem ice age, that renders all but the most equatorial areas uninhabitable, there would be a gigantic war for what is left to live in. Every nation (or some unions of nations) would try and conquer most of the remaining inhabitable areas as fast as possible. As their homeland becomes more and more uninhabitable, even women, children and old people start migrating and waging war. And so would the current inhabitants of those areas as soon as they figure out, that in case of defeat they would not be spared. Alliances would emerge as quickly as they get betrayed all for a chunk of farmable land.

The ice age could for example be caused by some major volcanic eruptions, clouding the sky for multiple decades to come.


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