Cortes Brings Down the Aztec Empire
Eleven ships and 500 men, reinforced by thousands of resentful Aztec rivals, topple an empire of millions in two years
Quick facts
- Spanish commander
- Hernan Cortes
- Expedition size
- 11 ships, about 500 men (1519)
- Tenochtitlan falls
- 13 August 1521
- Key factor
- Native alliances plus a smallpox epidemic
What happened
In 1519, drawn by rumors of gold and sophisticated inland cities, Hernan Cortes led an expedition of eleven ships and about 500 men to Mexico. He marched inland toward Tenochtitlan, the Aztec capital built on an island in a lake, gathering thousands of native allies from peoples who resented Aztec rule and forming a partnership with an enslaved Nahua woman, La Malinche, who served as his translator and adviser. A smallpox epidemic, likely carried by a member of a Spanish resupply expedition, swept through the Valley of Mexico while Tenochtitlan was already under siege, killing the emperor Cuitlahuac and an estimated third to half of the population in the worst-hit areas. Tenochtitlan fell to Spanish and allied forces on 13 August 1521. Pre-contact population estimates for the Valley of Mexico range from 15 to 20 million; within a century the same region held perhaps two to three million people, though historians treat the exact figures as approximate given gaps in surviving Spanish records.
Why it matters
The conquest handed Spain control of central Mexico's wealth and population within two years of Cortes's landing, and it established the model, alliance-building with local rivals plus the accidental weapon of Old World disease, that Pizarro would repeat against the Inca a decade later. The Aztec Empire's own detailed history, from its founding through its height under Moctezuma II, belongs to its own timeline.
How we know
The Library of Congress's Cortes and the Aztecs exhibit and the Mariners' Museum's entry on Cortes both describe the expedition's size, the alliances Cortes built, and the smallpox epidemic's toll, drawing on period Spanish accounts including Cortes's own letters to the crown; population decline figures are treated as estimates because of inconsistencies in surviving colonial census records.
Sources
- The Mariners' Museum and Park. Hernan Cortes · Reputable sourceexploration.marinersmuseum.org · The domain "exploration.marinersmuseum.org" is on our Reputable source registry. · Link is live and its text matches the event's key terms (Jul 2026)
- Library of Congress, Exploring the Early Americas. Cortes and the Aztecs · Primary source (author-declared)loc.gov · Cited as a "primary" source (no stronger domain match). · Link is live and its text matches the event's key terms (Jul 2026)
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Related timelines
- The Aztec Empire → · The Aztec Empire's own timeline covers its rise from Aztlan through the Triple Alliance to this conquest in full detail.