HRH Charles's 15-Great Grandmother. PM Cameron's 17-Great Grandmother. HRH Albert II's 16-Great Grandmother. Louis XVII's 11-Great Grandmother. HM Juan Carlos' 14-Great Grandmother. Philippe of Belgium's 14-Great Grandmother. HM Manuel II's 13-Great Grandmother. Grand Duke Henri's 14-Great Grandmother. HM Margrethe II's 14-Great Grandmother. HM Beatrix's 14-Great Grandmother. HM Constantine II's 14-Great Grandmother. HM Carl XVI Gustaf's 14-Great Grandmother. HM Harald V's 14-Great Grandmother. Ksr Wilhelm II's 12-Great Grandmother. HM Umberto II's 14-Great Grandmother. Boris Johnson's 16-Great Grandmother. `Red Baron' Richthofen's 14-Great Grandmother.