Like water, air, and earth, fire also had its special god. His name indicates the great antiquity of his cult, for the Aztecs called him Huehue-teotl, which means "the old god," and he was always pictured as an old man.

In contrast to the young Tezcatlipoca, who was the first to arrive at the feast of the month of Teotleco, Huehueteotl was the last to appear at the reunion of the gods. The old Teotihuacan culture, which flourished during the first centuries of the Christian era, represented him as an old man burdened with age and bearing on his head an enormous brazier. His stooped back, his toothless mouth, and the wrinkles at the corners of his lips give him his characteristic appearance of decrepitude.

But the god of fire appears not only in Teotihuacan but also in other contemporary cultures and even in older ones. Indeed, this god appears on a brazier found at the Olmec site of the hill of Las Mesas and on Zapotec urns. What is perhaps the oldest figure of him that has been discovered was found in an archaeological site in the Valley of Mexico where the Ticoman culture was in full flower when the volcano Xitle erupted, several centuries before the Christian era.

The god of fire undoubtedly represents one of the oldest conceptions of Mesoamerican man. He was the god of the center position in relation to the four cardinal points of the compass, just as the tlecuil, or brazier for kindling fire, was the center of the indigenous home and temple. For this reason, the figure of the cross is frequently found on the priests of the god, just as it is also found adorning the great incense pots called tlemaitl—literally "hands of fire"—in which the priests burned incense to the gods. To be sure, a god as old as this one also had many attributes. He was called Xiuhtecuhtli, which means "the lord of the year," "the lord of grass," or "the lord of turquoise," since the word xiuhuitl, with a slight variation in intonation, means all three things. He is frequently pictured carrying a kind of blue mitre made of turquoise mosaic work, which distinguished the Mexican kings and was called xiuhuitzolli. His nahual, or disguise, was the Xiuhcoatl, or the serpent of fire. It is characterized, as has been said, by a kind of horn decorated with the figures of seven stars and worn over the nose.

In the discussion of the stone called the Aztec Calendar the two serpents, or fire dragons, were mentioned that transport the sun on his course through the sky; and on two sides of the pyramid of Tenayuca, a temple dedicated to the worship of the sun, there are serpents of fire painted black or blue to indicate the two dragons, from the North and from the South, which carry the sun on his path.

Thus the nocturnal Tezcatlipoca and the diurnal Huitzilopochtli, were also gods of fire, and occasionally donned Xiuhcoatl, the nahual peculiar to Xiuhtecuhtli.

Many ceremonies and sacrifices were dedicated to this god, and at one of the crudest ceremonies men were burned in his honor.

But Xiuhtecuhtli as god of the year was also of great importance. During one of the most elaborate festivals, celebrated every eight years, when the 584-day period of the planet Venus and the years of the sun form a cycle, a great ceremony was held in honor of Xiuhtecuhtli, and the first month of the year, Izcalli, was dedicated to the worship of this particular god.

According to legend, a man and woman discovered fire, and when they had done so, they began to roast fish to eat, but the gods, angered at the boldness of the discovery made without their consent, cut off their heads and changed them into dogs.

In Mexican mythology, as in Greek mythology, the bold man capable of getting possession of fire, symbol of human power, without the consent of the gods, must be punished; he pays with his life for having the audacity to think that men are sufficient unto themselves to solve their problems.