Aztec Empire Timeline

In 1426, the Tepanec king Tezozomoc died, setting the stage for a succession crisis among his potential heirs.

The death of Tezozomoc precipitated a civil war between potential successors to the Tepanec throne, destabilizing the region and creating an opportunity for Tenochtitlan.

In 1427, Tenochtitlan, Texcoco, Tlacopan, and Huexotzinco went to war against Azcapotzalco, the dominant power in the Valley of Mexico.

Image source: Azcapotzalco (altepetl)

The coalition of Tenochtitlan, Texcoco, Tlacopan, and Huexotzinco emerged victorious over Azcapotzalco in 1428, ending Tepanec dominance in the Valley of Mexico.

These three city-states ruled the area in and around the Valley of Mexico from 1428 until the combined forces of the Spanish conquistadores and their native allies under Hernán Cortés defeated them in 1521.

After the Nahuas formed the empire in 1428 and began its program of expansion through conquest, the altepetl remained the dominant form of organization at the local level.

Before the reign of Nezahualcoyotl (1429–1472), the Aztec empire operated as a confederation along traditional Mesoamerican lines.

After the war, Huexotzinco withdrew, and in 1430 the three remaining cities—Tenochtitlan, Texcoco, and Tlacopan—formed a treaty now known as the Triple Alliance.

By the time the Spanish arrived in 1519, the lands of the alliance were effectively ruled from Tenochtitlan, while other partners of the alliance had taken subsidiary roles.

Native historical accounts say that these wars were instigated by Tlacaelel as a means of appeasing the gods in response to the massive drought that gripped the Basin of Mexico from 1450 to 1454.

Image source: Flower war

The expansion of the empire was briefly halted by the major four-year drought that hit the Basin of Mexico in 1450, and several cities in Morelos had to be re-conquered after the drought subsided.

A massive drought gripped the Basin of Mexico from 1450 to 1454, devastating agriculture and prompting religious and military responses from the Mexica leadership.

In 1455, the Purépecha under their king Tzitzipandaquare invaded the Toluca Valley, claiming lands previously conquered by Motecuzoma and Itzcoatl.

Image source: Purépecha Empire

In 1472, Axayacatl re-conquered the Toluca Valley region and successfully defended it from Purépecha attempts to take it back.

In 1479, Axayacatl launched a major invasion of the Purépecha Empire with 32,000 Aztec soldiers.

In 1515, Aztec armies commanded by the Tlaxcalan general Tlahuicole invaded the Purépecha Empire once again.

The Spanish expedition leader Hernán Cortés landed in Yucatán in 1519 with approximately 630 men, most armed with only a sword and shield.

Image source: Hernán Cortés

Reform efforts underway in the empire were cut short by the Spanish conquest that began in 1519.

Image source: Fall of Tenochtitlan

A second, larger Spanish expedition arrived in 1520 under the command of Pánfilo de Narváez, sent by Diego Velásquez with the goal of arresting Cortés for treason.

Image source: Pánfilo de Narváez

Cortés kept him prisoner and tortured him for a period of several years before finally executing him in 1525, marking the final end of Aztec resistance leadership.

Image source: Cuauhtémoc