Unless you are very stringent about unaffected and unchanged, all the books I listed should fulfill those criteria. While people obviously believe more in ghosts and goblins, the actual supernatural and magical is still elusive and hidden, with history continuing down its course with no obvious otherwordly influence. I am aware that there are books where Napoleon rides a dragon over the Alps, but the closest I've read to something like that is The Dragon Waiting. To me, historical fantasies are akin to franchise fiction, where the writers have to find their own little niche to tell stories in without upsetting the rest of the product line.