Disclaimer: I do not own any Buffy or POTC characters. They belong to their respected owners.
On the hellmouth nothing is impossible, myths become real and legends come to life. So if you think that something is not real because it is a myth, think twice. This is what Willow thought about the myth of one of her ancestors. Willow was told that her many great grand mothers royalty of some sort, but she could not believe that she was of royalty. Where was all the pomp and flare if that was so. So Willow believed that it was just a legend her family made up to look better in the eyes of the world. That is until her eighteenth birthday, everything changed that day. For her mother gave her a special gift.