The high plains in the center of modern Mexico, called the
Mexican Plateau or "altiplano", is one of the most important areas of
Mesoamerica. The altiplano extends over what is now the
Distrito Federal, most of the states of
Puebla,
Tlaxcala and
Mexico State as well as parts of the states of
Morelos and
Hidalgo. Sophisticated cultures were developed by peoples such as the
Nahuas, the
Tlahuicas and the Matlatzincas. The second stage is dated from 750-900 C.E. show simultaneous occupation of both the Ojo de Agua site and the northern edge of Tetepetl Hill, by the same ethnic group. The first constructions of the Teotenango site date from this period, including the
temazcal, structures 2C and 3C and some structures that lie under structures in Conjuntos A and C. The reason the settlement moved from the valley floor to the mesa was due to natural defenses that the mesa provided. Constructions here still are mostly of dwellings of
adobe and still show strong Teotihuacan influence indicated by two inclined walls supporting a vertical one. During the third stage (900 – 1162 CE), most of the currently visible structures of the ceremonial center, such as the pyramidal bases for temples, were built. Of these constructions, the ball court and the Serpent Base stand out. Some residences were also built. The beginning of the fourth stage (1162-1476) is characterized by the conquest and takeover of the city by the Matlatzincas. They added some small constructions to the ceremonial center, and amplified some other structures, but are mostly credited with the construction of the city's massive defenses, such as the wall on the west side. During the time the city's population grew significantly, with residential areas spreading toward the south. The Matlatzincas extended the domain of this city to include the entire Valley of Toluca, which major outposts in Toluca,
Calixtlahuaca,
Tenancingo. The fifth and final stage (1474-1550 C.E.) is characterized by the conquest of Teotenango by the emperor
Axayacatl and subsequent Aztec occupation of the city and the valley. Some Aztec architectural influence is felt with the best examples being Building 1C, and the narrow staircase built into the western defense wall. It also includes the initial stages of resettlement of the population of Teotenango to new Spanish colonial village of Tenango de Valle (also known as "Village of Teotenango") on the valley floor below. This resettlement was completed by 1550, after which the site above was completely abandoned. ==Excavation of the site==