Tula

Tula is located in a valley in the modern-day state of Hidalgo near the Sierra de Pachuca, and is watered by the Saldo and Tula Rivers. There is some evidence to suggest that Teotihuacan groups already had contact with the Tula region during the Classic period at sites such as Chingú, probably to obtain certain resources such as limestone from which to produce stucco. The first occupation at Tula might have taken place as early as A.D. 650, when a group coming from the north or west settled in Tula together with the local population. According to certain historical documents, the migratory groups were the Tolteca-Chichimeca (Toltecs), who established themselves near modern Tulancingo prior to populating Tula. Tula's foundation also is linked in some sources to a celebrated group of artisans (the Nonoalca) from the Gulf Coast.

The first substantial occupation (especially in Tula Chico) took place during the Corral phase ( A.D. 800-900). The entire Coyotlatelco complex, from the Bajío to the Valley of Mexico, is integrally related. The end of the Corral phase is critical since it prefigures Tula's appearance as a powerful state.

The wealth of their palaces, the talent of their artisans, their knowledge of herbs, medicine, minerals, calendars, and astronomy, their wisdom and devotion to gods such as Quetzalcoatl, all are characteristics attributed to the Toltecs. According to the scholar Paul Kirchoff, the Toltec Empire, composed of peoples of different origins, languages, and customs, was made up of four external provinces and four interior ones with Tula at the center, thus corresponding to the "four directions" of the universe. Kirchoff attributes the end of Tula not to the invasion of the Chichimeca (who had arrived at the site when it was already in ruins) but to a migration of Culhua people who lived to the west of the empire. There is evidence that Tula Grande was sacked and burned around A.D. 1150-1200. There are also some indications of the decline in city life prior to abandonment of the site. Tula reached its greatest extent during the Tollan phase ( A.D. 950-1150/1200). The Tula Chico complex was abandoned completely, a cult center dedicated to the Huastec deity Ehecatl was established near the El Corral complex, and Tula Grande became the sociopolitical axis of the city