Human sacrifice was a common practice in many cultures throughout history, but none took it to the extent that the Aztecs did. The Mexica people, who ruled over what is now known as the Aztec Empire in central Mexico, believed in a creation myth where the god Quetzalcoatl used the bones of humans from the fourth iteration of the sun and his own blood to create the current humans. The fifth sun was created by the god Huitzilopochtli, who sacrificed himself to become the sun so he could nourish the world. However, his sister Coyolxauhqui, the goddess of the moon, hated him and wanted to destroy him.

Huitzilopochtli needed the help of humans through human sacrifice, auto-sacrifice, and religious rituals to successfully fight off his sister every night. While there are variations of this creation myth, the central themes of the Aztec religion remain the same. The Aztecs saw human sacrifice as the ultimate sacrifice to offer to their gods, and this practice was prevalent in their society.

The sources of information about the Aztec Empire and their religion are often dubious, and the definition of the word Aztec is ambiguous, but understanding the religion is necessary to comprehend why a civilized society would create such an institution of human sacrifice.