John H. Ingram - Claimants to Royalty (1882)
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A look at imposters throughout history who claimed to be royalty. Chapters such as "The False Charlotte of Russia", "The False Zaga Christ of Abyssinia", "The False Nero of Rome", "The False Richard the Second of England" and "The False Alexis, Emperor of the East" should give an idea. There's an entire chapter on false Dauphins - I remember reading that there were around a hundred or so total. I even once saw a book on Masonic history that stated the Dauphin was an American Mason.
Another of Ingram's books, on haunted houses of England, was previously posted. I'm sorry there doesn't seem to be an online version of his The Philosophy of Hand-Writing.