Well, I live in a state that owes its name to fanfic: California is named after the island of California, home of Queen Calafia, her beautiful black amazons and their man-eating griffins, as all detailed in Garcia Ordonez de Montalvo's Las Sergas de Esplandian, which was the Sword of Shanarra of its day, a highly unauthorized but popular sequel to the much more highly respected Amadis de Gaul, more The Lord of the Rings of its day. At the end of Don Quixote, Cervantes had this to say about Esplandian: "Verily the father's goodness shall not excuse the want of it in the son. Here, good mistress housekeeper, open that window and throw it into the yard. Let it serve as a foundation to that pile which we are to set a-blazing presently."
That being said, Las Sergas de Esplandian was the pulp novel the conquistadores had on board when they sailed around and encountered the Baja peninsula. What's more, when the Portola party went up the coast, thinking the descriptions in LSdE were based on actual travelers' tales, they thought the California condors were Queen Calafia's big black man-eating griffins.
And so on to the present day where California is ruled by Conan the Barbarian.