In Aztec mythology, Xiuhtecuhtli [ʃiʍˈtekʷt͡ɬi] ("Turquoise Lord" or "Lord of Fire"), was the god of fire, day and heat. He was the lord of volcanoes, the personification of life after death, warmth in cold (fire), light in darkness and food during famine. He was also named Cuezaltzin [kʷeˈsaɬt͡sin] ("flame") and Ixcozauhqui [iʃkoˈsaʍki], and is sometimes considered to be the same as Huehueteotl ("Old God"), although Xiuhtecuhtli is usually shown as a young deity. His wife was Chalchiuhtlicue. Xiuhtecuhtli is sometimes considered to be a manifestation of Ometecuhtli, the Lord of Duality, and according to the Florentine Codex Xiuhtecuhtli was considered to be the father of the Gods, who dwelled in the turquoise enclosure in the center of earth. Xiuhtecuhtli-Huehueteotl was one of the oldest and most revered of the indigenous pantheon. The cult of the God of Fire, of the Year, and of Turquoise perhaps began as far back as the middle Preclassic period. Turquoise was the symbolic equivalent of fire for Aztec priests. A small fire was permanently kept alive at the sacred center of every Aztec home in honor of Xiuhtecuhtli.
The Nahuatl word xihuitl means "year" as well as "turquoise" and "fire", and Xiuhtecuhtli was also the god of the year and of time. The Lord of the Year concept came from the Aztec belief that Xiuhtecuhtli was the North Star. In the 260-day ritual calendar, the deity was the patron of the day Atl ("Water") and with the trecena 1 Coatl ("1 Snake"). Xiuhtecuhtli was also one of the nine Lords of the Night and ruled the first hour of the night, named Cipactli ("Alligator"). Scholars have long emphasized that this fire deity also has aquatic qualities. Xiuhtecuhtli dwelt inside an enclosure of turquoise stones, fortifying himself with turquoise bird water. He is the god of fire in relation to the cardinal directions, just as the brazier for lighting fire is the center of the house or temple. Xiuhtecuhtli was the patron god of the Aztec emperors, who were regarded as his living embodiment at their enthronement. The deity was also one of the patron gods of the pochteca merchant class.