# The Siege of Tenochtitlan's Secret Weapon: Smallpox and Epidemics in the Conquest

Page: https://stenobird.com/podcast/the-conquistadors-exploration-greed-and-destruction-fexingo-history-7864470/the-siege-of-tenochtitlan-s-secret-weapon-smallpox-and-epidemics-in-the-conquest
Text version: https://stenobird.com/podcast/the-conquistadors-exploration-greed-and-destruction-fexingo-history-7864470/the-siege-of-tenochtitlan-s-secret-weapon-smallpox-and-epidemics-in-the-conquest.md
Podcast: [The Conquistadors: Exploration, Greed, and Destruction — Fexingo History](https://stenobird.com/podcast/the-conquistadors-exploration-greed-and-destruction-fexingo-history-7864470)
Published: 2026-07-01T15:57:20+00:00
Episode link: https://audio.fexingo.com/history/the-conquistadors/episode-0129.mp3
Audio file: https://audio.fexingo.com/history/the-conquistadors/episode-0129.mp3
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Duration seconds: 493

## Resource

When Hernán Cortés and his Indigenous allies besieged Tenochtitlan in 1521, they had a secret ally they barely understood: smallpox. This episode explores the role of epidemic disease in the fall of the Aztec Empire, focusing on the 1520 smallpox outbreak that killed Moctezuma's successor Cuitláhuac and devastated the city's defenders. We discuss the arrival of smallpox with the Pánfilo de Narváez expedition, the cocoliztli epidemics that followed, and how disease may have killed more people than swords and arquebuses combined. Drawing on the Florentine Codex and modern paleopathological research, we examine how native populations with no prior exposure suffered mortality rates as high as 50%, while the Spanish carried partial immunity. The conversation also touches on the biological exchange of the Columbian Exchange and the ethical questions it raises. A sobering look at how microbes shaped the conquest as much as men did. #Smallpox #Cocoliztli #Tenochtitlan #HernanCortes #Cuauhtemoc #Cuitlahuac #FlorentineCodex #Pandemic #Mesoamerica #AztecEmpire #ColumbianExchange #Epidemic #BernalDiaz #Narvaez #History #FexingoHistory #NewSpain #Conquistadors Keep every episode free: buymeacoffee.com/fexingo

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