HUITZILOPOCHTLI ("hummingbird of the south") was the most powerful god in Aztec religion. The tribal god of the wandering Méxica, he became the patron deity of the Aztec ceremonial capital, Tenochtitlán (1325–1521). Primary sources depict the dual nature of the god, including a human aspect as left-handed warrior hero and a divine aspect as the solar god who kills the powers of the night. Both aspects express a single fact about Huitzilopochtli: He was a terrible, overwhelming warrior who completely dominated his enemies.

At the time of the Spanish conquest in 1521, Huitzilopochtli's shrine was situated, along with that of the rain god Tlaloc, on top of the largest pyramid in the Aztec empire, the Templo Mayor (Great Temple) of Tenochtitlán. His spectacular religious development from a tribal god to the principal god of the imperial capital is reflected in two mythical episodes that were ritually celebrated...