Charles Ottley Groom, Charles Ottley Groom Napier, also self-styled Charles de Bourbon d'Este Paleologus Gonzaga, Prince of Mantua and Montferrat (14 May 1839 – 17 January 1894) was an English natural history collector, writer, best known however as an impostor, charlatan, and fraud. Aside from claiming a royal lineage, he attempted to rise in social standing by awarding a so-called "Mantua Medal" to noted artists, writers, and scientists of his time.