HM Juan Carlos' 19-Great Uncle. Philippe of Belgium's 19-Great Uncle. Grand Duke Henri's 19-Great Uncle. HM Margrethe II's 19-Great Uncle. HM Beatrix's 15-Great Grandfather. HM Constantine II's 17-Great Grandfather. Wm. von Bismarck's 12-Great Grandfather. `Red Baron' Richthofen's 14-Great Grandfather.