HRH Charles's 18-Great Grandmother. Lady Diana's 19-Great Grandmother. HM Juan Carlos' 19-Great Grandmother. Philippe of Belgium's 19-Great Grandmother. Grand Duke Henri's 19-Great Grandmother. HM Margrethe II's 17-Great Grandmother. HM Beatrix's 15-Great Grandmother. HM Constantine II's 16-Great Grandmother. HM Carl XVI Gustaf's 16-Great Grandmother. Ksr Wilhelm II's 16-Great Grandmother. Wm. von Bismarck's 12-Great Grandmother. `Red Baron' Richthofen's 14-Great Grandmother.