The Valley of Mexico is part of the central highlands and lies at an altitude of about a mile and a half. At the low point of the Valley there is a large lake that made human life sustainable in the generally dry country. Long before the Aztecs came to the Valley of Mexico the land had seen the rise and decline of a number of other tribal groups. One of these groups built the great city of Teotihuacán. From Teotihuacán its people built an empire. This was during the period of the fourth to the sixth centuries A.D. About 600 A.D. the empire of Teotihuacán was overthrown. Centuries later another empire was created by the people of the city of Tollan (Tula), known as the Toltecs. Their empire lasted from about the tenth to the twelfth century. Near the end of the twelfth century Tula was captured and burned by its enemies. The Aztecs did not come to the Valley of Mexico until the fourteenth century.

Despite the rise and fall of empires there was a continuity of culture in the Valley of Mexico. Agriculture and other technologies were passed down from generation to generation. A religion evolved as each dominant group absorbed the gods and rituals of their predecessors. The temples often survived the collapse of an empire. The pyramidal temples of Teotihuacán were honored and utilized by the Aztecs seven centuries after the demise of the Teotihuacán empire.

Many gods survived in the culture of the Valley of Mexico but one particular one is of special historical interest, the feathered serpent Quetzalcoatl. Depictions of Quetzalcoatl are found in Teotihuacán. The Toltecs also worshipped Quetzalcoatl and one king was identified with Quetzalcoatl. That king, personifying Quetzalcoatl, was apparently driven from power and journeyed with his supporters to the Gulf Coast and sailed away vowing to return one day to claim his kingdom. That legend survived several centuries and was a part of the culture of the Aztecs when Cortez and his conquistadores appeared on that same coast.

The Aztecs arrived in the Valley of Mexico as homeless wanderers about 1300 A.D. They had to eke out a precarious existence by allying themselves with more powerful tribes in the area. They finally settled on a marshy island in the Lake. The Aztecs were successful in retaining this site in part because it was generally an undesirable location in part it was at an interstice of local empires. Any tribal group considering capturing the Aztecs and their territory risked provoking their more powerful neighbors into a major war. So the Aztecs were left to build their island and a city upon it. The city was called Tenochtitlán after a name the Aztecs used for themselves, Tenochca. The other name they used for themselves was Mexica. They did not call themselves Aztecs.

The founding date of Tenochtitlán was 1325 A.D. The Aztecs of this early Tenochtitlán had accepted the overlordship of the Tepanecs of the city of Azcapotzalco. The Tepanecs were expansionists and defeated the rival empire of Texcoco, but over-reaching leaders of the Tepanecs brought into existence a coalition of peoples who defeated the Tepanecs and restored Texcoco. That coalition included the Tlaxcalans from outside the Valley, a people who were later the crucial allies of Cortez. From the political turmoil following the collapse of Tepanec power the Aztecs emerged as an independent force. They acquired some territory on the shore of the Lake and formed an alliance with Texcoco and Tlacopan, the Triple Alliance. The terms of the Triple Alliance called for the division of any spoils of war into five parts, two parts of which would go to Tenochtitlán, two parts to Texcoco and one part to Tlacopan.

The Triple Alliance built an empire. Later Tlacopan faded from power and for a period of time Tenochtitlán and Texcoco jointly ruled the empire. By the reign of Montezuma II, the Aztec leader who later faced Cortez, Texcoco had also declined and Tenochtitlán ruled the empire of the Triple Alliance alone. The map below shows the area controlled by the Triple Alliance in red. The area shown in pink indicates tribes allied with the Aztecs. The area shown in light green is the area controlled by the bitter enemies of the Aztecs, the Tlaxcalans.

The Economy of the Valley of Mexico

The economy of the Valley of Mexico was founded upon the growing of corn (maize). This plant is a native of the region. It was planted by use of a digging stick. Without a plow and draft animals corn could be cultivated only on the lightest soils, the soils that were deposited by rivers and streams. Corn depletes the minerals it requires in a few years so unless a means of refertilization is available the corn farmers would have to move on to new land after several years.

The Aztecs farming of the marshlands was fortunate in that water was readily available and the marshlands had abundant decaying vegetations that helped refertilize the farm plots. Aztecs created chinampas, narrow garden plots surrounded by water. This arrangement allowed them to use fertile mud dredged from the lake bottom to fertilize their crops.

A typical size for a chinampa was about 20 feet wide by 300 feet long. There was considerable variation in these dimensions. On the chinampas the Aztec farmers grew squash and tomatoes in addition to corn. Several crops could be grown each year.

The land was farmed by individual families but ultimate ownership rested with the clan. If a family could not farm the land under their care its control reverted to the clan to reassignment to another family. Families had to contribute a share of their farm and household craft production as taxes. They also had to provide labor for religious and community functions and manpower in times of war.