Xiuhcoatl

Xiuhcoatl means Turquoise Serpent — or equally Year Serpent, for the Nahuatl word xihuitl covers turquoise, year, and grass at once. It is a serpent of living fire, scaled like burning gemstone: an upcurved, star-studded snout, a back divided into segments, and a tail ending in the trapeze-and-ray sign that marks the year. It embodies the sun's burning heat, and was read too as the falling meteor and the lightning bolt; the fire god Xiuhtecuhtli bears it on his back, and it serves as the litter that carries the sun Tonatiuh across the daytime sky.

As a weapon it belongs to Huitzilopochtli. On Coatepec, Serpent Hill, the war god seized the Xiuhcoatl in the instant of his birth and with one stroke of fire cut off the head of the moon goddess Coyolxauhqui, casting her body down the slope — the famous scene recorded in Book 3 of the Florentine Codex. Each winter the festival of Panquetzaliztli restaged the battle: a priest carrying a paper-and-pine fire serpent raced down from the temple summit and burned it in the plaza below, like a meteor striking the earth.

Aztec craftsmen returned to the image constantly. Two colossal Xiuhcoatl encircle the rim of the Sun Stone, their heads meeting face to face at the bottom of the disk; a celebrated double-headed serpent pectoral in the British Museum, its undulating body sheathed in tiny turquoise plates, is often linked to the fire serpent; and several fire-serpent sculptures from the Templo Mayor now stand in the site museum beside the Coyolxauhqui stone.