[[File: Flower_Collage.jpg|250px|thumbnail|left| Early Colonial Spanish Collage Depicting an Aztec Flower War]]
The Aztecs of Mexico built the largest and most powerful empire in the Pre-Columbian world. The Aztec Empire encompassed most of what is central and southern Mexico today and its influence spread beyond the Rio Grande River in the north and into the rain forests of central America to the south. In many ways, the structure of the Aztec Empire was not unlike that of old world pre-modern societies, especially those from the Bronze Age, but the fundamental difference was that it was driven by a unique combination of warfare and human sacrifice. The Aztecs were by far the best and most organized warriors of the region and the nearly constant wars they waged were not only to spread the geographic limits of their empire, but also to acquire more captives for human sacrifice, especially for the warrior god Huitzilopochtli.
[[File: Jaguar_warrior.jpg|250px|thumbnail|left| Early Spanish Depiction of an Aztec Jaguar Warrior]]
An examination of the expansion of the Aztec Empire reveals that there were both standard reasons for the expansion as well as uniquely Aztec factors. The standard reason for any empire to expand, no matter the period or the people, is the control of resources. When the Triple Alliance expanded to control most of central and southern Mexico, precious luxury goods such as jade, obsidian, and bird feathers were brought to the cities of the Central Valley to be traded in the markets. The Aztec economy was essentially a market system and therefore needed a steady supply of exotic and precious goods coming to the markets in order to keep the economy moving. <ref> Townsend, pgs. 83-99</ref> The control of resources was a vital part of the Aztec Empire’s success and among those resources were human captives taken in war.
Perhaps the most unique reason for the expansion of the Aztec Empire was the need for more human sacrifice victims. The Aztecs believed that human blood was needed to ensure the planting cycle and the arrival of water in the form of rain. Human sacrifice was also a way to appease specific gods, such as the warrior god Huitzilopochtli, who specifically desired live hearts
, and other deities associated with kingship and coronation festivals. Finally, the ever bellicose Aztecs also employed human sacrifice for practical reasons. The constant public spectacles of human sacrifice served to desensitize the Aztec people to violence in general and specifically toward their enemies, and on the other hand it demoralized and weakened the resolve of their enemies – those who opposed the Aztecs knew that they faced being the victims of mass sacrifice rituals on the top of their pyramids. <ref> Townsend, pgs. 74-77.</ref> Because warfare played such an integral role in the Aztec Empire, the warriors were among the most exulted members of society.