Lake Texcoco

Colonial-era Nahua accounts, including the pictorial Codex Mendoza and the oral histories recorded by Sahagun and Duran, describe the Mexica arriving at Lake Texcoco as the last stage of a long migration from a legendary homeland called Aztlan, guided along the way by the counsel and omens of their patron god Huitzilopochtli. On a marshy, largely undesirable island near the lake's western shore, already ringed by longer-established and more powerful city-states, the Mexica are said to have seen an eagle perched on a nopal cactus, in some tellings grasping a serpent, the specific sign Huitzilopochtli had promised would mark the end of their wandering and the location of their future capital.

Tenochtitlan's foundation on this unpromising, marginal site in 1325 CE was itself remembered as proof of divine rather than merely practical selection, since the Mexica held none of the political standing that would otherwise have secured them better land, and the lake's waters, canals and chinampa agricultural islands became inseparable from the city's identity and its later imperial rise.

Tenochtitlan's builders treated the lake as more than a physical setting, laying the city out with its great ceremonial precinct and the Templo Mayor at the intersection of causeways running to the cardinal directions, an arrangement scholars generally read as expressing the Aztec conception of their capital as the fixed center of the cosmos, itself encircled by the surrounding waters much as Mesoamerican cosmology more broadly pictured the inhabited earth as an island set within a cosmic sea. The chinampa system, artificial garden islands built up from lakebed mud and reeds, extended this relationship into daily agricultural life, drawing sustenance directly from the same waters that framed the city's religious geography.

The lake's physical extent did not survive Spanish colonization intact. Colonial and later Mexican drainage projects, undertaken chiefly to control flooding, progressively emptied most of Lake Texcoco over the centuries following the conquest, so that the religious and cosmological landscape the Mexica built their capital around now survives mainly in the documentary and archaeological record rather than in the lake itself, a small fraction of which remains today east of modern Mexico City.