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Note: Aaron Gertler is cross-posting this on behalf of AI Impacts. The original author is Daniel Kokotajlo.


Epistemic status: I am not a historian, nor have I investigated these case studies in detail. I admit I am still uncertain about how the conquistadors were able to colonize so much of the world so quickly. I think my ignorance is excusable because this is just a blog post; I welcome corrections from people who know more. If it generates sufficient interest I might do a deeper investigation. Even if I’m right, this is just one set of historical case-studies; it doesn’t prove anything about AI, even if it is suggestive. Finally, in describing these conquistadors as “successful,” I simply mean that they achieved their goals, not that what they achieved was good. 


In the span of a few years, some minor European explorers (later known as the conquistadors) encountered, conquered, and enslaved several huge regions of the world. That they were able to do this is surprising; their technological advantage was not huge. (This was before the scientific and industrial revolutions.) From these cases, I think we learn that it is occasionally possible for a small force to quickly conquer large parts of the world, despite:

  1. Having only a minuscule fraction of the world’s resources and power
  2. Having technology + diplomatic and strategic cunning that is better but not that much better
  3. Having very little data about the world when the conquest begins
  4. Being disunited

Which all suggests that it isn’t as implausible that a small AI takes over the world in mildly favorable circumstances as is sometimes thought.

Three shocking true stories

I highly recommend you read the wiki pages yourself; otherwise, here are my summaries:


 [wiki] [wiki]

  • April 1519: Hernán Cortés lands in Yucatan with ~500 men, 13 horses, and a few cannons. He destroys his ships so his men won’t be able to retreat. His goal is to conquer the Aztec empire of several million people.
  • He makes his way towards the imperial capital, Tenochtitlán. Along the way he encounters various local groups, fighting some and allying with some. He is constantly outnumbered but his technology gives him an advantage in fights. His force grows in size, because even though he loses Spaniards he gains local allies who resent Aztec rule.
  • Tenochtitlán is an island fortress (like Venice) with a population of over 200,000, making it one of the largest and richest cities in the world at the time. Cortés arrives in the city asking for an audience with the Emperor, who receives him warily.
  • Cortés takes the emperor hostage within his own palace, indirectly ruling Tenochtitlán through him.
  • Cortés learns that the Spanish governor has landed in Mexico with a force twice his size, intent on arresting him. (Cortés’ expedition was illegal!) Cortés leaves 200 men guarding the Emperor, marches to the coast with the rest, surprises and defeats the new Spaniards in battle, and incorporates the survivors into his army.
  • July 1520: Back at the capital, the locals are starting to rebel against his men. Cortés marches back to the capital, uniting his forces just in time to be besieged in the imperial palace. They murder the emperor and fight their way out of the city overnight, taking heavy losses.
  • They shelter in another city (Tlaxcala) that was thinking about rebelling against the Aztecs. Cortés allies with the Tlaxcalans and launches a general uprising against the Aztecs. Not everyone sides with him; many city-states remain loyal to Tenochtitlan. Some try to stay neutral. Some join him at first, and then abandon him later. Smallpox sweeps through the land, killing many on all sides and causing general chaos.
  • May 1521: The final assault on Tenochtitlán. By this point, Cortés has about 1,000 Spanish troops and 80,000 – 200,000 allied native warriors. He had 16 cannons and 13 boats. The Aztecs have 80,000 – 300,000 warriors and 400 boats. Cortés and his allies win.
  • Later, the Spanish would betray their native allies and assert hegemony over the entire region, in violation of the treaties they had signed.


 [wiki]  [wiki]

  • 1532: Francisco Pizarro arrives in Inca territory with 168 Spanish soldiers. His goal is to conquer the Inca empire, which was much bigger than the Aztec empire.
  • The Inca empire is in the middle of a civil war and a devastating plague.
  • Pizarro makes it to the Emperor right after the Emperor defeats his brother. Pizarro is allowed to approach because he promises that he comes in peace and will be able to provide useful information and gifts.
  • At the meeting, Pizarro ambushes the Emperor, killing his retinue with a volley of gunfire and taking him hostage. The remainder of the Emperor’s forces in the area back away, probably confused and scared by the novel weapons and hesitant to keep fighting for fear of risking the Emperor’s life.
  • Over the next months, Pizarro is able to leverage his control over the Emperor to stay alive and order the Incans around; eventually he murders the Emperor and makes an alliance with local forces (some of the Inca generals) to take over the capital city of Cuzco.
  • The Spanish continue to rule via puppets, primarily Manco Inca, who is their puppet ruler while they crush various rebellions and consolidate their control over the empire. Manco Inca escapes and launches a rebellion of his own, which is partly successful: He utterly wipes out four columns of Spanish reinforcements, but is unable to retake the capital. With the morale and loyalty of his followers dwindling, Manco Inca eventually gives up and retreats, leaving the Spanish still in control.
  • Then the Spanish ended up fighting each other for a while, while also putting down more local rebellions. After a few decades Spanish dominance of the region is complete. (1572).


 [wiki]  [wiki]  [wiki]

  • 1506: Afonso helps the Portuguese king come up with a shockingly ambitious plan. Eight years prior, the first Europeans had rounded the coast of Africa and made it to the Indian Ocean. The Indian Ocean contained most of the world’s trade at the time, since it linked up the world’s biggest and wealthiest regions. See this map of world population (timestamp 3:45). Remember, this is prior to the Industrial and Scientific Revolutions; Europe is just coming out of the Middle Ages and does not have an obvious technological advantage over India or China or the Middle East, and has an obvious economic disadvantage. And Portugal is a just tiny state on the edge of the Iberian peninsula.
  • The plan is: Not only will we go into the Indian Ocean and participate in the trading there — cutting out all the middlemen who are currently involved in the trade between that region and Europe — we will conquer strategic ports around the region so that no one else can trade there!
  • Long story short, Afonso goes on to complete this plan by 1513. (!!!)

Some comparisons and contrasts:

  • Afonso had more European soldiers at his disposal than Cortes or Pizarro, but not many more — usually he had about a thousand or so. He did have more reinforcements and support from home.
  • Like them, he was usually significantly outnumbered in battles. Like them, the empires he warred against were vastly wealthier and more populous than his forces.
  • Like them, Afonso was often able to exploit local conflicts to gain local allies, which were crucial to his success.
  • Unlike them, his goal wasn’t to conquer the empires entirely, just to get and hold strategic ports.
  • Unlike them, he was fighting empires that were technologically advanced; for example, in several battles his enemies had more cannons and gunpowder than he did.
  • That said, it does seem that Portuguese technology was qualitatively better in some respects (ships, armor, and cannons, I’d say.) Not dramatically better, though.
  • While Afonso’s was a naval campaign, he did fight many land battles, usually marine assaults on port cities, or defenses of said cities against counterattacks. So superior European naval technology is not by itself enough to explain his victory, though it certainly was important.
  • Plague and civil war were not involved in Afonso’s success.

What explains these devastating conquests?

Wrong answer: I cherry-picked my case studies.

History is full of incredibly successful conquerors: Alexander the Great, Ghenghis Khan, etc. Perhaps some people are just really good at it, or really lucky, or both.

However: Three incredibly successful conquerors from the same tiny region and time period, conquering three separate empires? Followed up by dozens of less successful but still very successful conquerors from the same region and time period? Surely this is not a coincidence. Moreover, it’s not like the conquistadors had many failed attempts and a few successes. The Aztec and Inca empires were the two biggest empires in the Americas, and there weren’t any other Indian Oceans for the Portuguese to fail at conquering.

Fun fact: I had not heard of Afonso before I started writing this post this morning. Following the Rule of Three, I needed a third example and I predicted on the basis of Cortes and Pizarro that there would be other, similar stories happening in the world at around that time. That’s how I found Afonso.

Right answer: Technology

However, I don’t think this is the whole explanation. The technological advantage of the conquistadors was not overwhelming.

Whatever technological advantage the conquistadors had over the existing empires, it was the sort of technological advantage that one could acquire before the Scientific and Industrial revolutions. Technology didn’t change very fast back then, yet Portugal managed to get a lead over the Ottomans, Egyptians, Mughals, etc. that was sufficient to bring them victory. On paper, the Aztecs and Spanish were pretty similar: Both were medieval, feudal civilizations. I don’t know for sure, but I’d bet there were at least a few techniques and technologies the Aztecs had that the Spanish didn’t. And of course the technological similarities between the Portuguese and their enemies were much stronger; the Ottomans even had access to European mercenaries! Even in cases in which the conquistadors had technology that was completely novel — like steel armor, horses, and gunpowder were to the Aztecs and Incas — it wasn’t god-like. The armored soldiers were still killable; the gunpowder was more effective than arrows but limited in supply, etc.

(Contrary to popular legend, neither Cortés nor Pizarro were regarded as gods by the people they conquered. The Incas concluded pretty early on that the Spanish were mere men, and while the idea did float around the Aztecs for a bit the modern historical consensus is that most of them didn’t take it seriously.)

Ask yourself: Suppose Cortés had found 500 local warriors, gave them all his equipment, trained them to use it expertly, and left. Would those local men have taken over all of Mexico? I doubt it. And this is despite the fact that they would have had much better local knowledge than Cortés did! Same goes for Pizarro and Afonso. Perhaps if he had found 500 local warriors led by an exceptional commander it would work. But the explanation for the conquistador’s success can’t just be that they were all exceptional commanders; that would be positing too much innate talent to occur in one small region of the globe at one time.

Right answer: Strategic and diplomatic cunning

This is my non-expert guess about the missing factor that joins with technology to explain this pattern of conquistador success.

They didn’t just have technology; they had effective strategy and they had effective diplomacy. They made long-term plans that worked despite being breathtakingly ambitious. (And their short-term plans were usually pretty effective too, read the stories in detail to see this.) Despite not knowing the local culture or history, these conquistadors made surprisingly savvy diplomatic decisions. They knew when they could get away with breaking their word and when they couldn’t; they knew which outrages the locals would tolerate and which they wouldn’t; they knew how to convince locals to ally with them; they knew how to use words to escape militarily impossible situations… The locals, by contrast, often badly misjudged the conquistadors, e.g. not thinking Pizarro had the will (or the ability?) to kidnap the emperor, and thinking the emperor would be safe as long as they played along.

This raises the question, how did they get that advantage? My answer: they had experience with this sort of thing, whereas locals didn’t. Presumably Pizarro learned from Cortés’ experience; his strategy was pretty similar. (See also: the prior conquest of the Canary Islands by the Spanish). In Afonso’s case, well, the Portuguese had been sailing around Africa, conquering ports and building forts for more than a hundred years.

Lessons I think we learn

I think we learn that:

It is occasionally possible for a small force to quickly conquer large parts of the world, despite:

  1. Having only a minuscule fraction of the world’s resources and power
  2. Having technology + diplomatic and strategic cunning that is better but not that much better
  3. Having very little data about the world when the conquest begins
  4. Being disunited

Which all suggests that it isn’t as implausible that a small AI takes over the world in mildly favorable circumstances as is sometimes thought.

Having only a minuscule fraction of the world’s resources and power

In all three examples, the conquest was more or less completed without support from home; while Spain/Portugal did send reinforcements, it wasn’t even close to the entire nation of Spain/Portugal fighting the war. So these conquests are examples of non-state entities conquering states, so to speak. (That said, their claim to represent a large state may have been crucial for Cortes and Pizarro getting audiences and respect initially.) Cortés landed with about a thousandth the troops of Tenochtitlan, which controlled a still larger empire of vassal states. Of course, his troops were better equipped, but on the other hand they were also cut off from resupply, whereas the Aztecs were in their home territory, able to draw on a large civilian population for new recruits and resupply.

The conquests succeeded in large part due to diplomacy. This has implications for AI takeover scenarios; rather than imagining a conflict of humans vs. robots, we could imagine humans vs. humans-with-AI-advisers, with the latter faction winning and somehow by the end of the conflict the AI advisers have managed to become de facto rulers, using the humans who obey them to put down rebellions by the humans who don’t.

Having technology + diplomatic and strategic skill that is better but not that much better

As previously mentioned, the conquistadors didn’t enjoy god-like technological superiority. In the case of Afonso the technology was pretty similar. Technology played an important role in their success, but it wasn’t enough on its own. Meanwhile, the conquistadors may have had more diplomatic and strategic cunning (or experience) than the enemies they conquered. But not that much more–they are only human, after all. And their enemies were pretty smart.

In the AI context, we don’t need to imagine god-like technology (e.g. swarms of self-replicating nanobots) to get an AI takeover. It might even be possible without any new physical technologies at all! Just superior software, e.g. piloting software for military drones, targeting software for anti-missile defenses, cyberwarfare capabilities, data analysis for military intelligence, and of course excellent propaganda and persuasion.

Nor do we need to imagine an AI so savvy and persuasive that it can persuade anyone of anything. We just need to imagine it about as cunning and experienced relative to its enemies as Cortés, Pizarro, and Afonso were relative to theirs. (Presumably no AI would be experienced with world takeover, but perhaps an intelligence advantage would give it the same benefits as an experience advantage.) And if I’m wrong about this explanation for the conquistador’s success–if they had no such advantage in cunning/experience–then the conclusion is even stronger.

Additionally, in a rapidly-changing world that is undergoing slow takeoff, where there are lesser AIs and AI-created technologies all over the place, most of which are successfully controlled by humans, AI takeover might still happen if one AI is better, but not that much better, than the others.

Having very little data about the world when the conquest begins

Cortés invaded Mexico knowing very little about it. After all, the Spanish had only realized the Americas existed two decades prior. He heard rumors of a big wealthy empire and he set out to conquer it, knowing little of the technology and tactics he would face. Two years later, he ruled the place.

Pizarro and Afonzo were in better epistemic positions, but still, they had to learn a lot of important details (like what the local power centers, norms, and conflicts were, and exactly what technology the locals had) on the fly. But they were good at learning these things and making it up as they went along, apparently.

We can expect superhuman AI to be good at learning. Even if it starts off knowing very little about the world — say, it figured out it was in a training environment and hacked its way out, having inferred a few general facts about its creators but not much else — if it is good at learning and reasoning, it might still be pretty dangerous.

Being disunited

Cortés invaded Mexico in defiance of his superiors and had to defeat the army they sent to arrest him. Pizarro ended up fighting a civil war against his fellow conquistadors in the middle of his conquest of Peru. Afonzo fought Greek mercenaries and some traitor Portuguese, conquered Malacca against the  orders of a rival conquistador in the area, and was ultimately demoted due to political maneuvers by rivals back home.

This astonishes me. Somehow these conquests were completed by people who were at the same time busy infighting and backstabbing each other!

Why was it that the conquistadors were able to split the locals into factions, ally with some to defeat the others, and end up on top? Why didn’t it happen the other way around: some ambitious local ruler talks to the conquistadors, exploits their internal divisions, allies with some to defeat the others, and ends up on top?

I think the answer is partly the “diplomatic and strategic cunning” mentioned earlier, but mostly other things. (The conquistadors were disunited, but presumably were united in the ways that mattered.) At any rate, I expect AIs to be pretty good at coordinating too; they should be able to conquer the world just fine even while competing fiercely with each other. For more on this idea, see this comment.


Thanks to Katja Grace for feedback on a draft. All mistakes are my own, and should be pointed out to me via email at daniel@aiimpacts.org.

(Front page image from the Conquest of México series. Representing the 1521 Fall of Tenochtitlan, in the Spanish conquest of the Aztec Empire)





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What about diseases? I admit I know little about this period of history, but the accounts I read (for example in Guns, Germs and Steel) place the advantage in the spread of diseases to the Americas.

Basically, because the Americas lacked many big domesticated mammals, they could not have cities like European ones with cattle everywhere. The conditions of living in these big cities caused the spread of diseases. And when going to the Americas, the conquistadors took these diseases with them to a population which had never experienced them, causing most of the deaths of the early conquests.

(This is the picture from the few sources I've read. So it might be wrong or inaccurate, but if it is, I am very curious of why.)

Diseases are probably part of the explanation for Cortes' and Pizarro's success, but not Afonso. Also, Cortes got pretty far into his conquest before disease became an issue. Perhaps the disease enabled the Spanish to betray their allies and dominate the region after Tenochtitlan fell though? I'm not sure.

I suspect insofar as diseases are part of the explanation, it's by the intermediate step of sowing chaos that the conquistadors could exploit.

Later on, diseases would play a much bigger and more direct role, by reducing the native population to the point where they couldn't compete with the influx of european settlers. The east coast of America might look different, for example, if there had been 20x more people living there when the colonists started arriving.

Insofar as we think this was an important part of the story, I guess our conclusion would be that a moderate tech and experience advantage combined with general chaos and disruption can allow a tiny group to dominate a much larger region.

This is all my uninformed opinion though, don't take it too seriously.

combined with general chaos and disruption

That chaos and disruption is critical. Even before Cortes set foot, death from disease made native societies very weak and easy to conquer. 1493 deals with this aspect.

Interesting, I didn't know disease hit the Aztecs before Cortes arrived. I thought he brought the disease himself. Thanks for the tip, perhaps I'll go read that book!

I'm reading it now; it is indeed a very good book. I don't think it supports the claim that disease hit the Aztecs before Cortes arrived--it makes a brief one-sentence claim to that effect, but other sources (e.g. wikipedia) say the opposite, and give more details (e.g. they say it arrived with the expedition sent to capture Cortes). And of course there's still Afonso.

Update: Turns out it returns to the topic of Cortes at the end of the book. It confirms what wikipedia says, that smallpox arrived after Cortes had already killed the emperor and fled the city. I think it also exaggerates the role of smallpox even then, actually -- it makes it sound like Cortes' "first assault" on the city failed because the city was too strong and then his "second assault" succeeded because it was weakened by disease. But (a) his "first assault" was just him and his few hundred followers killing the Emperor and escaping, and his "second assault" came after a long siege and involved 200,000 native warriors helping him plus additional Spaniards with siege weapons etc. Totally different things. And (b) smallpox didn't just strike Tenochtitlan, it hit everywhere, including Cortes' native allies. And (c) The final battle for Tenochtitlan was intense; he didn't exactly walk in over the corpses of smallpox-ridden defenders, he had to fight his way in against a gigantic army of determined defenders. So I still stand by my claim that disease had fairly little to do with Cortes' victory, even though 1493, a book which I otherwise respect, says otherwise. (And by "fairly little" I mean "not so much that my conclusions in the post are undermined.")

Thanks for this post, fascinating read!

Considering the hypothesis given here, I'm curious as to why we don't see more takeovers today. There are countries and small corporations involved in inner conflicts that I expect (following this post) a small but powerful organisation (or a large nation) could take over. Some reasons that we may not see this - 

  1. International laws or one of the world's leading nations might punish such takeover attempt.
  2. People with position of power may not want to take that kind of risk.
  3. There is not that much economic value to gain.
  4. Takeovers may be quiet (say by blackmail).
  5. Conspiratorially, the relevant opportunities are getting picked up by the more powerful nations/corporations.

If you really want to know I suggest this book. But it's pretty dry reading so let me sum up what I got out of it. Logistics of war have changed a lot and it changes the economics of conquest. Before guns, everything you needed could be supplied from your enemy's countryside. Conquest was economically useful to the conqueror because you could take your surplus population of single men and feed them and maybe otherwise enrich them at the enemy's expense instead of your own. But the more stuff you need that can't be taken directly from nature or from a farm, the more of a supply chain you have to establish. Gunpowder was the first issue. But then guns evolved, and you went from re-using bullets that were just little metal balls that could be picked up from the battlefield and re-used to bullets that had to precision-manufactured to fit a rifled barrel. And on and on. Now you need oil, and modern standards of living mean you have to give the troops better food and housing and medical care, and none of your vehicles or weapons or fancy communication equipment can be replaced by pillaging the countryside. Whatever you get from the damaged country you conquer isn't going to be as valuable as what you spent to get it.

So if the economics of conquest were to change back in some fundamental way, or the non-economic goals of the actors changed enough to make them able and willing to pay the economic price, then there probably would be more conquest.

Good question! Isn't there a stereotype of CIA agents funding coups in various countries, to install US puppet regimes? Insofar as this is a correct description of what's been happening, it seems like a modern example of what I'm talking about. A small number of people with an intel and tech advantage over the locals, promising to represent a faraway greater power, engages in some intrigue and allies with some local factions and somehow ends up on top. Admittedly, this isn't as clear of an example as it could be.

I think part of the issue is that these days there just aren't that many isolated military conflicts. Most military conflicts these days are but minor theatres of a much bigger cold war between great powers. (This is perhaps my take on your #1 and #5)

1491: New Revelations of the Americas Before Columbus Paperback – October 10, 2006
by Charles C. Mann

1493: Uncovering the New World Columbus Created Paperback – July 24, 2012
by Charles C. Mann

I found those books useful and interesting on the question of conquest. Disease and death from disease I think is the reason for dismantling of local empires. The same did not happen in the rest of the world.

Alexander, Genghis Khan and others like that routinely rose and fell over millenia, those stories are spread in time. The Americas are a different story because of the disease vector.

Thanks for the tip. I agree that disease seems important in the Cortes and Pizarro cases, but what about Afonso?

There have always been wars, victors, conquered in history, I consider Afonso as just one more example of the same.

Thanks for these comments; I've updated the original post in light of them!

First, thanks! I had no idea Afonso de Albuquerque's conquests had been so marvelous. I mean, yeah, Camões and Pessoa dedicated him some verses, but it's not very informative.


Why didn’t it happen the other way around: some ambitious local ruler talks to the conquistadors, exploits their internal divisions, allies with some to defeat the others, and ends up on top

Actually, it happened sometimes - natives played Europeans against each other in Africa and Brazil, where the absence of centralized government (and bad terrain) made a quick takeover impossible.

First, thanks! I had no idea Afonso de Albuquerque's conquests had been so marvelous

I would not call any conquest marvelous

When I read Ramiro's comment, I assumed that they were referring to the other common definition of marvelous ("causing great wonder; extraordinary" rather than "extremely good or pleasing"). I don't know whether English is their first language, but I've seen people for whom English isn't a first language use "positive" English words (e.g. "incredible") in ways that are technically correct, but not common in the U.S. (e.g. "this can't possibly be true").

To provide a sillier example, calling the Great Pyramids of Giza a "wonder of the world" doesn't necessarily imply that you think a project created by slave labor was "wondrous" in the sense of being good -- you could instead mean that the Pyramids are unusually large/interesting/well-constructed compared to other architecture of the ancient world, or something like that.

In any case, if you see a comment that makes you think someone is endorsing a very harmful/problematic view, it seems best to ask a clarifying question when the situation is ambiguous.

Thanks Aaron. I try not to assume anything, and usually ask for clarification. I should have done the same here.

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