The term, Aztec, is a startlingly imprecise term to describe the culture that dominated the Valley of Mexico in the fifteenth and sixteenth centuries.
Properly speaking, all the Nahua-speaking peoples in the Valley of Mexico were Aztecs, while the culture that dominated the area was a tribe of the Mexica (pronounced “me-shee-ka”) called the Tenochca (“te-noch-ka”). At the time of the European conquest, they called themselves either “Tenochca” or “Toltec,” which was the name assumed by the bearers of the Classic Mesoamerican culture. The earliest we know about the Mexica is that they migrated from the north into the Valley of Mexico as early as the twelfth century AD, well after the close of the Classic Period in Mesoamerica. They were a subject and abject people, forced to live on the worst lands in the valley. They adopted the cultural patterns (called Mixteca-Pueblo) that originated in the culture of Teotihuacán, so the urban culture they built in the fifteenth and sixteenth centuries is essentially a continuation of Teotihuacán culture.
The peoples of Mesoamerica distinguished between two types of people: the Toltec (which means “craftsman”), who continued Classic urban culture, and the Chichimec, or wild people, who settled Mesoamerica from the north. The Mexica were, then, originally Chichimec when they migrated into Mexico, but eventually became Toltecs proper.
The history of the Tenochca is among the best preserved of the Mesoamericans. They date the beginning of their history to 1168 and their origins to an island in the middle of a lake north of the Valley of Mexico. Their god, Huitzilopochtli, commanded them on a journey to the south and they arrived in the Valley of Mexico in 1248. According to their history, the Tenochca were originally peaceful, but their Chichimec ways, especially their practice of human sacrifice, revolted other peoples who banded together and crushed their tribe. In 1300, the Tenochcas became vassals of the town of Culhuacan; some escaped to settle on an island in the middle of the lake. The town they founded was Tenochtitlan, or “place of the Tenochcas.”
A peice of Mayan Jade showing the high level of artistry achieved by mesoamerican craftsmen.
Relations between the Tenochcas and Culhuacan became bitter after the Tenochcas sacrificed a daughter of the king of Culhuacan; so enraged were the Culhuacans that they drove all the Tenochcas from the mainland to the island. There, the Tenochcas who had lived in Culhuacan taught urban culture and architecture to the peoples on the island and the Tenochcas began to build a city. The city of Tenochtitlan is founded, then, sometime between 1300 and 1375.
The Tenochcas slowly became more powerful and militarily more skilled, so much so that they became allies of choice in the constant conflicts between the various peoples of the area. The Tenochcas finally won their freedom under Itzacoatl (1428-1440), and they began to build their city, Tenochtitlan, with great fervor. Under Itzacoatl, they built temples, roads, a causeway linking the city to the mainland, and they established their government and religious hierarchy. Itzacoatl and the chief who followed him Mocteuzma I (1440-1469) undertook wars of conquest throughout the Valley of Mexico and the southern regions of Vera Cruz, Guerrero, and Puebla. As a result, Tenochtitlan grew dramatically: not only did the city increase in size, precipitating the need for an aqueduct system to bring water from the mainland, it grew culturally as well as the Tenochcas assimilated the gods of the region into their religion.
A succession of kings followed Mocteuzma I until the accession of Mocteuzma II in 1502; despite a half century of successful growth and conquest, Tenochca culture and society began to suffer disasters under Mocteuzma II. First, tribute peoples began to revolt all over the conquered territories and it is highly likely that Tenochca influence would eventually have declined by the middle of the sixteenth century. Most importantly, the reign of Mocteuzma II was interrupted by the invasion of the Spaniards under Cortez in 1519-1522.