House of Bourbon-Parma
Prince Sixtus of Bourbon-Parma (; 1 August 1886 – 14 March 1934) was a member of the House of Bourbon-Parma, a Belgian officer in World War I, and the central figure in the Sixtus Affair, an attempt to negotiate a treaty to end Austria-Hungary's participation in the Great War separate from its Central Powers allies. He also wrote a number of books.