This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
Panquetzaliztli, the raising of banners, is the fifteenth of the eighteen veintenas that make up the xiuhpohualli, the Aztec solar year, and it is the one veintena built entirely around a single deity's own myth. Huitzilopochtli was the Mexica's patron god, credited with leading their ancestors out of Aztlan and into the Basin of Mexico, and Panquetzaliztli was his feast.
Sahagun's informants describe the festival as a reenactment of Huitzilopochtli's own birth story: born fully armed from his mother Coatlicue after she was impregnated by a ball of feathers, he immediately fought off an attack from his sister Coyolxauhqui and their four hundred siblings, the Centzon Huitznahua, who resented their mother's pregnancy as a family disgrace. Huitzilopochtli killed Coyolxauhqui and scattered or killed most of her allies, and the myth was read at Tenochtitlan as the founding charter of Mexica dominance, the god's own victory standing behind every victory the empire claimed afterward.
The veintena's rites, banners raised over the city and a reenactment of the battle at Coatepec among them, are described at unusual length in the Florentine Codex, reflecting how central this one myth was to how the Mexica understood their own history. The Great Temple's own layout, with Huitzilopochtli's shrine built beside a stone believed to represent Coyolxauhqui's dismembered body, is often read by archaeologists as the myth built into architecture, meant to be walked past on the way to the god's own sanctuary.
Panquetzaliztli falls late in the solar year, with only Atemoztli, Tititl and Izcalli following it before the Nemontemi close the count, a placement that set the empire's own founding myth near the year's turn rather than at its start.