Remains of earliest human inhabitation of the area have been found on the nearby Cerro (Hill) de Ecatepec. The area was initially settled by successive waves of Otomis; however, because of the later arrival of Toltec-Chichimecas that dominated the rest of the Valley of Mexico, this area eventually assimilated to the rest of the Valley, ending with its domination by the Aztec Empire.[1] Ecatepec was an Aztec altepetl or city-state in the Valley of Mexico.