In Aztec mythology, Xiuhtecuhtli ("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 ("flame") and Ixcozauhqui , 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.