The Aztecs were a people who settled in a valley in central Mexico in the 14th century. The word 'Aztec' derives from Aztlán, a possibly-mythological place north of their eventual empire, where the Aztecs believed their tribe originated. The Aztecs referred to themselves as Mexica, a term of disputed origin, from which the modern name of Mexico derives.

The Aztecs followed a dream-prophecy to the shores of Lake Texcoco. Their sun god, Huitzilopochtli, instructed them that if they found an eagle on a cactus eating a snake, that was where they should found their city. So it was that Tenochtitlan was built out over Lake Texcoco, since subsumed by modern day Mexico City.

The Aztecs moved into a populated area, and were not welcomed by those who preceded them. They were considered barbaric by the Toltecs and others in the region, but they quickly assimilated much of their neighbors' culture. Through conquest and intermarriage, they created an empire based more on the payment of tribute than actual loyalty and common administration. This no doubt made them easy prey for conquest in turn by the European invaders in the 16th century.

The Aztec society was a highly structured one, with nobility, priests, warriors and peasants. Slavery was common, but was not hereditary or necessarily life-long. Warriors gained status by the number of captives they acquired, not the number of 'enemy' they killed. Captives were used as trade items and sacrifices.

The Aztecs achieved an advanced level of civilization for the period, with Tenochtitlan's peak population being greater than that of any contemporaneous European city. They had a well-developed written language, art, poetry, a detailed calendar and sciences. But the aspect of their culture that occasions the greatest interest is their system of human sacrifice. Most of the mesoamerican cultures of the period practiced some form of sacrifice, but the Aztecs' reputation in this regard dwarfed that of their contemporaries.

The Aztecs believed their gods required human blood, in payment for divine blood spilled to create mankind, for instance, or to insure that the sun continued to provide light for the following year. The sun god Huitzilopochtli was the focus of most sacrificial rites, although other Aztec gods were also paid such tributes. Sacrifices took place at least during the eighteen annual festivals, and typically consisted of tributes being forced to climb the steps to the top of the temple pyramid, where they were held by priests as their hearts were cut out. The bodies were tumbled back down the stairs, while the hearts were burned as the sacrifice. Reports of eighty thousand captives being sacrificed at a four-day ceremony are difficult to believe and are considered by many to be more propaganda than truth.

Anthropologists disagree on the topic of cannibalism among the Aztecs; some, notably Marvin Harris, claim that the bodies of sacrificial victims were ritually butchered and parceled out to be eaten among the elite. This practice, according to some, was to make up for a diet deficient in protein due to the overhunting of large game in the area. Others claim the evidence for cannibalism was either invented or exaggerated by the Spanish conquerors of the area as justification for their intervention.

Whatever the case, the Aztec civilization was conquered by Spanish conquistadors led by Cortez (alternatively Cortes) in 1521. The settlers who followed the invaders managed over the next few decades to suppress and ultimately to eradicate the Aztec culture and language.