Itzcoatl ("Obsidian Serpent") was the fourth tlatoani (emperor) of the Aztecs, ruling from 1427 (or 1428) to 1440, the period when the Mexica threw off the domination of the Tepanecs and laid the foundations for the eventual Aztec Empire. Itzcoatl was an illegitimate son of Acamapichtli, the first Aztec tlatoani. He himself was elected as tlatoani when his predecessor, Chimalpopoca, was killed by Maxtla of the nearby Tepanec city-state of Azcapotzalco. Allying with Nezahualcoyotl of Texcoco, It… (More on Itzcoatl)