Codex Borbonicus, p. 9, a Mexica calendar book painted around the time of the Spanish conquest.
Key myth
Born fully armed from Coatlicue to kill his sister Coyolxauhqui and his four hundred brothers (the Centzonhuitznahua) as they attacked their mother. The Templo Mayor was dedicated to him and Tlaloc.
Where sources differ or caution applies. Histoyre du Mechique lists him as a son of Ometeotl; the Florentine Codex says Coatlicue.