The earliest well-defined settlements in the Tula area appear around 400 BCE.
Tula was probably settled by people of various ethnic backgrounds which may have included the Nonoalcas and the Chichimecas from the south and north respectively.
The area probably was under the political control of Teotihuacan in the Epiclassic period, according to Teotihuacan designs found on Tula pottery.
The area's lime deposits were probably an important source for the plaster used in construction.
At this time Tula was a small urban settlement with modest public architecture concentrated at Tula Chico (Small Tula).
The constructions at Tula Chico are smaller than those in other Epiclassic sites, and was probably a minor player in the political and economic activity of the time.
Tula Chico's occupation is from 650 to 900.
From 650 to 750, Tula Chico developed, and at its height spanned five to six km², parts of which may be buried under Tula Grande.
The population was somewhere between 19,000 and 27,000 at its height.
Tula Chico was abandoned between 850 and 900CE, and Tula Grande began to develop.
After the decline of Teotihuacan, there was a power vacuum with city states dominating small regions.
Tula ceramics change during this period, as styles and techniques come under new influences.
 At the same time, settlement patterns of the area significantly changed with occupation mostly on hilltops and high hillsides.
Architecture and pottery show influence from the west and north, with some from the east, suggesting a multiethnic population.

The city rose to prominence after the fall of Teotihuacan and reached its height between 900 and 1150.
Although Tula Grande (Big Tula) grew to be larger than anything contemporary with it, it never grew to the size of Teotihuacan.
The city at its height probably covered 14km² with a population of about 60,000 with another 20,000 to 25,000 in the surrounding 1000km², dominated by the ceremonial center of Tula Grande.
Urban and rural house units indicated the importance of extended family groups but the scale of these seemed to have become smaller over time.
Tula had defensive fortification at Las Ranas and Toluquilla against the Chichimecas.
Its political sphere is thought to include most of the present state of Hidalgo, into the Valley of Mexico and possibly into the Toluca Valley and the Bajío.
Much of this is done by comparison of ceramics but this can indicate political or economic influence.

At that time, Tula was a fertile region near obsidian mines and on an important trade route.
Its economic base was agriculture and the mining and crafting of obsidian.
It appears the craft was practiced by about half of the occupants, along with the working of travertine and ceramics, taking over this function from Teotihuacan.
Tula probably did not rule an empire but may have ruled a regional state.
Long range contacts are indicated by the appearance of ceramics from eastern Mesoamerica, grey-green plumbate from southern Guatemala and polychrome ceramics from Costa Rica.
Tula probably traded obsidian in return.
The socioeconomics of Tula society is thought to have consisted of a ruling elite class, a craftsmen class, a merchant class and a large number of farm workers.
Most of the farm workers were outside Tula proper with most of the other classes in the city.
Excavations in the area have found evidence of the cultivation of chili peppers, amaranth, squash and maguey along with corn and beans.
A number of wild plants were harvested including mesquite beans and cactus fruit.
There is evidence of domesticated turkey and dog.
Irrigated corn was the most important crop with anywhere from 3000 to 10000 hectares cultivated.
It may not have been enough to feed the large population.
There is an unoccupied area varying from one to three km wide which was probably agricultural.
It has been proposed that the area received more rainfall during the Classic period than now which may have allowed for more large scale agricultural production without irrigation.

It is probable that they had a form of hieroglyphic writing system
The earliest well-defined settlements in the Tula area appear around 400 BCE. Tula was probably settled by people of various ethnic backgrounds which may have included the Nonoalcas and the Chichimecas from the south and north respectively. The area probably was under the political control of Teotihuacan in the Epiclassic period, according to Teotihuacan designs found on Tula pottery. The area's lime deposits were probably an important source for the plaster used in construction. At this time Tula was a small urban settlement with modest public architecture concentrated at Tula Chico (Small Tula). The constructions at Tula Chico are smaller than those in other Epiclassic sites, and was probably a minor player in the political and economic activity of the time. Tula Chico's occupation is from 650 to 900. From 650 to 750, Tula Chico developed, and at its height spanned five to six km², parts of which may be buried under Tula Grande. The population was somewhere between 19,000 and 27,000 at its height. Tula Chico was abandoned between 850 and 900CE, and Tula Grande began to develop. After the decline of Teotihuacan, there was a power vacuum with city states dominating small regions. Tula ceramics change during this period, as styles and techniques come under new influences.  At the same time, settlement patterns of the area significantly changed with occupation mostly on hilltops and high hillsides. Architecture and pottery show influence from the west and north, with some from the east, suggesting a multiethnic population.
The city rose to prominence after the fall of Teotihuacan and reached its height between 900 and 1150. Although Tula Grande (Big Tula) grew to be larger than anything contemporary with it, it never grew to the size of Teotihuacan. The city at its height probably covered 14km² with a population of about 60,000 with another 20,000 to 25,000 in the surrounding 1000km², dominated by the ceremonial center of Tula Grande. Urban and rural house units indicated the importance of extended family groups but the scale of these seemed to have become smaller over time. Tula had defensive fortification at Las Ranas and Toluquilla against the Chichimecas. Its political sphere is thought to include most of the present state of Hidalgo, into the Valley of Mexico and possibly into the Toluca Valley and the Bajío. Much of this is done by comparison of ceramics but this can indicate political or economic influence.
At that time, Tula was a fertile region near obsidian mines and on an important trade route. Its economic base was agriculture and the mining and crafting of obsidian. It appears the craft was practiced by about half of the occupants, along with the working of travertine and ceramics, taking over this function from Teotihuacan. Tula probably did not rule an empire but may have ruled a regional state. Long range contacts are indicated by the appearance of ceramics from eastern Mesoamerica, grey-green plumbate from southern Guatemala and polychrome ceramics from Costa Rica. Tula probably traded obsidian in return. The socioeconomics of Tula society is thought to have consisted of a ruling elite class, a craftsmen class, a merchant class and a large number of farm workers. Most of the farm workers were outside Tula proper with most of the other classes in the city. Excavations in the area have found evidence of the cultivation of chili peppers, amaranth, squash and maguey along with corn and beans. A number of wild plants were harvested including mesquite beans and cactus fruit. There is evidence of domesticated turkey and dog. Irrigated corn was the most important crop with anywhere from 3000 to 10000 hectares cultivated. It may not have been enough to feed the large population. There is an unoccupied area varying from one to three km wide which was probably agricultural. It has been proposed that the area received more rainfall during the Classic period than now which may have allowed for more large scale agricultural production without irrigation.
It is probable that they had a form of hieroglyphic writing system
Tula (Mesoamerican site)