Start with the chronology
The smallpox epidemic described in accounts of the conquest of Mexico belongs to 1520, after Cortés’s arrival in 1519. The Florentine Codex includes representations of people affected by the epidemic. Getty’s discussion of competing conquest narratives and its Summer 2020 magazine provide context for the manuscript and epidemic.
The codex was completed decades after the conquest. It must be read with attention to its compilation and the different voices within it, rather than treated as an unmediated transcript of 1520.
Why the original premise was misleading
The earlier article suggested that inviting disease could have enabled the population to thrive through enhanced immunity. That outcome was not supported by evidence. Exposure to a severe infectious disease is not equivalent to a safe or predictable population-wide defence.
A historical thought experiment should not give people knowledge or medical tools that the scenario has not plausibly supplied. Nor should it assume that diverse Indigenous societies would automatically adopt one shared political response.
A more useful question
Ask instead: how does an epidemic change the choices available to a society already facing war and political conflict?
Compare what the sources describe about illness with the wider narrative of conquest. Identify where a conclusion concerns disease, where it concerns military or political choices, and where the evidence does not let you separate them.
For an alternative-history exercise, imagine a reduced epidemic burden, clearly state that as a fictional assumption, and examine one limited consequence. Do not treat a different final outcome as inevitable.
Source exercise
Use the Library of Congress description of Book XII of the Florentine Codex to identify when and how the account was assembled. Ask whose experiences appear, whose are harder to recover, and how translation affects your reading.
Editorial review
Reviewed on 26 September 2026. Removed the unsupported deliberate-exposure premise, corrected the epidemic chronology and replaced blanket claims about Indigenous beliefs.