The Well at the World’s End (volume 1 and volume 2), by William Morris, Borgo Press, 2000. [Originally published 1896!]
This is considered the first fantasy novel set in its own world. William Morris was an artisan (leader of the Arts and Crafts movement), decorator, poet, producer of the first recliner chair, and all-around multi-talented guy. The story is of the heroic quest for the Well that gives long life. With its knights, archaic language, and reliance on a little more luck than seems common, you can see its influence on C. S. Lewis, Tolkien, and the rest of the fantasy genre. (Reviewed Oct., ’09) [The version I had was in one volume; I think these two are the equivalent together.]