He was the mythic leader and chief divinity of the Aztecs, dominant tribe of the Nahua nation.
The Aztecs, who called themselves Mejica or Mexicans after they had established themselves on the high table-land of Mexico, belong to a very large family or group of tribes speaking a common idiom called Nahua or Nahoa.
These Nahua-speaking tribes were called the Nahuatlaca, and compose a little more than one-fourth of the present Indian population.
In Mexico itself the languages of the Nahua nations, of which the Aztec is the best-known dialect, show no connexion of origin with the language of the Otomi tribes, nor either of these with the languages of the regions of the ruined cities of Central America, the Quiche of Guatemala and the Maya of Yucatan.
Earliest of the Nahua nations, the Toltecs are traditionally related to have left their northern home of Huehuetlapallan in the 6th century; and there is other evidence of the real existence of the nation.