The Acolhua are a Mesoamerican people who arrived in the Valley of Mexico in or around the year 1200 CE.Smith, p. 171, who arrives at this date by averaging 6 dates mentioned in early codices. The Acolhua were a sister culture of the Aztecs (or Mexica) as well as the Tepanec, Chalca, Xochimilca and others.
According to some researchers,Smith, p. 170. the ruling family of the Acolhua were descended from Otomi speakers and did not speak Nahuatl until decreed by their ruler (tlatoani) Techotlala.
Under Techotlala's grandson, Nezahualcoyotl, the Acolhua allied with the Mexica (Aztecs) in the Aztec Triple Alliance. The Acolhua capital, Texcoco, became a cultural center of the resultant Aztec Empire.