Just read your addition. Ummm, well, then get a book on French history or do a search for all the Kings and Queens of France on the internet. See which King and Queen was beheaded. Like I said though, just because there is a prince who fled does not prove you are related. You will have to trace your ancestry back to that person. It sounds like the story of the prince is real. As for your relationship, that is going to be the hard part to prove.