Poss. Lady Diana's 15-Great Uncle. HM Juan Carlos' 15-Great Uncle. Philippe of Belgium's 15-Great Uncle. Grand Duke Henri's 15-Great Uncle. HM Margrethe II's 14-Great Grandfather. HM Beatrix's 14-Great Uncle. HM Carl XVI Gustaf's 14-Great Grandfather. Wm. von Bismarck's 10-Great Uncle. `Red Baron' Richthofen's 12-Great Uncle.