" Quetzalcoatl, the Feathered Serpent, [...] came to teach [the ancient inhabitants of Mexico] the benefits of settled agriculture and the skills necessary to build temples. Although this deity is frequently depicted as a serpent, he is more often shown in human form--the serpent being his symbol and his alter ego--and is usually described as "a tall bearded white man" ... "a mysterious person ... a white man with a strong formation of body, broad forehead, large eyes and a flowing beard." Indeed, [...] the attributes and life history of Quetzalcoatl are so human that it is not improbable that he may have been an actual historical character ... the memory of whose benefactions lingered after his death, and whose personality was eventually deified. The same could very well be said of Oannes--and just like Oannes at the head of the Apkallu (likewise depicted as prominently bearded) it seems that Quetzalcoatl traveled with his own brotherhood of sages and magicians. We learn that they arrived in Mexico "from across the sea in a boat that moved by itself without paddles," and that Quetzalcoatl was regarded as having been "the founder of cities, the framer of laws and the teacher of the calendar. "

― Graham Hancock , Magicians of the Gods: The Forgotten Wisdom of Earth's Lost Civilization