In what year was the Aztec capital Tenochtitlan traditionally founded? The traditional answer is 1325.
The Mexica, often called the Aztecs, established Tenochtitlan on an island in Lake Texcoco in the Valley of Mexico. According to the foundation story, their patron deity Huitzilopochtli instructed them to settle where they saw an eagle perched on a prickly pear cactus, a scene later incorporated into Mexico’s national emblem.
The city grew from a difficult island settlement into the capital of a powerful empire. Mexica engineers expanded the island, built causeways and aqueducts, and used chinampa agriculture in the surrounding wetlands. Tenochtitlan eventually became one of the largest cities in the pre-Columbian Americas.
1325 is the conventional date used in histories and quizzes, but the precise foundation date is not certain. Some researchers have proposed 1345, and the specific date of March 13 was selected much later for a commemorative anniversary. The city was captured in 1521 and its ruins became the foundation of Mexico City.