Political map of North America & the Caribbean 1427 (Tepanec War): The Mexica—the last of a number of Nahua people who migrated from among the Chichimeca of northern Mexico to settle in the Valley of Mexico—founded Tenochtitlan on an island in Lake Texcoco in 1325. Rising to prominence as fierce warriors, they threw off the domination of the Tepanecs in 1427–28 and established the Triple Alliance of Tenochtitlan, Texcoco, and Tlacopan (Aztec Triple Alliance) soon after. This alliance would form the basis of what would become known as the Aztec Empire (“Aztec” being a mystical name for the Nahua).