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.”)