Poss. HRH Charles's 18-Great Uncle. HM Juan Carlos' 20-Great Uncle. Philippe of Belgium's 20-Great Uncle. Grand Duke Henri's 20-Great Uncle. HM Margrethe II's 19-Great Uncle. HM Beatrix's 13-Great Grandfather. HM Constantine II's 14-Great Grandfather. HM Carl XVI Gustaf's 14-Great Grandfather. Wm. von Bismarck's 10-Great Grandfather. `Red Baron' Richthofen's 13-Great Grandfather.