How do we know about Quetzalcoatl today?

Quetzalcóatl, Mayan name Kukulcán, (from Nahuatl quetzalli, “tail feather of the quetzal bird [Pharomachrus mocinno],” and coatl, “snake”), the Feathered Serpent, one of the major deities of the ancient Mexican pantheon. Representations of a feathered snake occur as early as the Teotihuacán civilization (3rd to 8th century CE) on the central plateau. At that time Quetzalcóatl seems to have been conceived as a vegetation god—an earth and water deity closely associated with the rain god Tlaloc.