HM George I's 6-Great Aunt. HRE Charles VI's 7-Great Aunt. HRH Charles's 15-Great Grandmother. Lady Diana's 15-Great Aunt. PM Cameron's 17-Great Grandmother. HRH Albert II's 17-Great Grandmother. Louis XVII's 11-Great Grandmother. HM Juan Carlos' 15-Great Grandmother. Philippe of Belgium's 15-Great Grandmother. HM Manuel II's 14-Great Grandmother. Grand Duke Henri's 15-Great Grandmother. HM Margrethe II's 15-Great Grandmother. HM Beatrix's 14-Great Grandmother. HM Constantine II's 15-Great Grandmother. HM Carl XVI Gustaf's 15-Great Grandmother. HM Harald V's 15-Great Grandmother. Ksr Wilhelm II's 13-Great Grandmother. HM Umberto II's 15-Great Grandmother. Wm. von Bismarck's 11-Great Aunt. Boris Johnson's 16-Great Grandmother. `Red Baron' Richthofen's 15-Great Grandmother.