Poss. Lady Diana's 16-Great Grandfather. HM Juan Carlos' 18-Great Uncle. Philippe of Belgium's 18-Great Uncle. Grand Duke Henri's 18-Great Uncle. HM Margrethe II's 18-Great Uncle. HM Beatrix's 14-Great Grandfather. Wm. von Bismarck's 11-Great Grandfather. `Red Baron' Richthofen's 14-Great Grandfather.