In 1426 the Tepanec ruler Tezozomoc died, leading to an uneasy succession as one son, Maxtla, usurped his elder half-brother Tayatzin. The Mexica city of Tenochtitlan rebelled against Maxtla’s authority, allying with Texcoco and other city states to sack the Tepanec capital of Azcapotzalco. After sacrificing Maxtla, the victorious cities formed the Triple Alliance of Tenochtitlan, Texcoco, and Tlacopan, laying the foundation of the Aztec Empire.
in wikipedia
Following the defeat of the Tepanecs and the formation of the Aztec Triple Alliance, Tenochtitlan emerged as the most powerful altapetl (city-state) in the Valley of Mexico. The king of Tenochtitlan, Itzcoatl, became effective leader of the Triple Alliance and quickly used his newfound power to consolidate Aztec control over the Valley of Mexico. During his reign (1427–1441), Itzcoatl conquered the remaining cities around Lake Texcoco in the middle of the valley before moving south to capture Cuauhnahuac (Cuernavaca).
in wikipedia
