Tlacopan (meaning "florid plant on flat ground"), also called Tacuba, was a Pre-Columbian Mesoamerican city-state situated on the western shore of Lake Texcoco. Founded by Tlacomatzin, Tlacopan was a Tepanec kingdom subordinate to nearby Azcapotzalco. Tlacopan sided with Tenochtitlan and Texcoco in their conquest of Azcapotzalco, becoming a member of the Triple Alliance which formed the nucleus of the Aztec Empire. The ruler of Tlacopan, Totoquihuaztli, then took the title Tepaneca tecuhtli, "Lo… (More on Tlacopan)