The Mexica Found Tenochtitlan and Build the Aztec Empire
Migrants with no land of their own found a city on a swampy lake island that becomes the seat of an empire of 200,000 people
Quick facts
- Founded
- c. 1325 CE, Lake Texcoco
- Triple Alliance formed
- 1428 CE
- Peak population (Tenochtitlan)
- Over 200,000
- Fell to Spanish forces
- 1521 CE
What happened
The Mexica, a migrant clan who arrived at Lake Texcoco with no territory of their own, founded Tenochtitlan around 1325 CE on a marshy island, building it into a planned city of causeways and floating garden plots (chinampas) that grew to more than 200,000 people. Through the Triple Alliance formed in 1428 with Texcoco and Tlacopan, the Mexica built an empire that took tribute from hundreds of city-states across central Mexico, reaching its height under Moctezuma II before the Spanish conquest ended it in 1521.
Why it matters
Tenochtitlan's ruins became the foundation, literally, of Mexico City, and the Aztec tribute network Cortes exploited by allying with subject city-states is what made the conquest possible with a few hundred Spaniards. This civilization has its own detailed timeline on this site.
How we know
Much of what is known about the Aztec comes from post-conquest Spanish chronicles and from Aztec accounts recorded after 1521, so population and tribute figures carry real uncertainty and are treated as such on the dedicated Aztec Empire timeline.
Sources
- World History Encyclopedia. Tenochtitlan · Reputable sourceworldhistory.org · The domain "worldhistory.org" is on our Reputable source registry. · Link is live and its text matches the event's key terms (Jul 2026)
- World History Encyclopedia. The Fall of Tenochtitlan · Reputable sourceworldhistory.org · The domain "worldhistory.org" is on our Reputable source registry. · Link is live and its text matches the event's key terms (Jul 2026)
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Related timelines
- The Aztec Empire → · The full Aztec story: migration from Aztlan, the Triple Alliance, Moctezuma II, and the 93-day siege that ended the empire.