The Aztec capital falls

Hernán Cortés and his Spanish force took Tenochtitlan with the help of tens of thousands of Indigenous allies, and with disease devastating the city. The conquest ended Aztec rule.

Context

Cortés first reached Tenochtitlan in November 1519 and was received by the ruler Moctezuma II. After the Spanish fled the city in June 1520 in the violent retreat known as the Noche Triste, they regrouped with allies, notably the Tlaxcalans, who had their own grievances against Aztec domination.

A smallpox epidemic, introduced to the region in 1520, killed many inhabitants of the island city, including the new ruler Cuitláhuac. The Spanish built boats to attack across Lake Texcoco and cut off food and water supplies. The final siege lasted roughly three months in 1521, and the last Aztec ruler, Cuauhtémoc, was captured on 13 August.

Death tolls from the siege are uncertain, and estimates of the size of the Indigenous allied force differ among sources. The Spanish later built Mexico City on the ruins, and the conquest opened the way to the colony of New Spain.

Our knowledge comes from both Spanish accounts, such as Cortés's letters and Bernal Díaz's memoir, and Indigenous sources written in Nahuatl after the conquest. These perspectives differ on events and motives, and modern historians compare them to build a fuller picture of the conquest and its aftermath.