Using Mythic Elements in Your Story by Anne Marie Gazzolo. Here are the opening paragraphs. Read the rest of the article at the link in this paragraph.
Many authors borrow from fairy-tales, myths, and legends and adapt or transform them to suit their own stories. I recently read The History of The Hobbit for a class and was struck by how many elements from Celtic and other mythologies J. R. R. Tolkien wove into his tale.
John Rateliff notes, “…the way in which Tolkien selected elements that fit what he needed for his story is instructive of his complex relationship with all his outside sources: he was neither a naive reader or a passive borrower but transformed and remade what he chose to take…” (History 532-33).
So should be any scribe who draws from the Cauldron of Story, as Tolkien calls the Pot on which the Soup has boiled ages-long. He addresses this in his delightful essay, “On Fairy-Stories,” which is must reading for anyone who aspires to the “elvish craft” of fantasy writing.