Under Itzcoatl the Mexica[2] of Tenochtitlan threw off the domination of the Tepanecs and established the Triple Alliance (Aztec Empire) together with the other city-states Tetzcoco and Tlacopan.
[3] He was elected as the king when his predecessor, his nephew Chimalpopoca, was killed by Maxtla of the nearby Tepanec āltepētl (city-state) of Azcapotzalco.
Allying with Nezahualcoyotl of Texcoco, Itzcoatl went on to defeat Maxtla and end the Tepanec domination of central Mexico.
Fresh water springs lining these shores had allowed the development of extensive raised gardens, or chinampas, set on the shallow lake floors.
Successful campaigns against Xochimilco (1430), Mixquic (1432), Cuitlahuac (1433), and Tezompa would secure agricultural resources for Tenochtitlan and, along with the conquest of Culhuacan and Coyoacán, would cement the Triple Alliance's control over the southern half of the Valley of Mexico.