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 Uncle. HM Beatrix's 14-Great Uncle. HM Constantine II's 15-Great Uncle. HM Carl XVI Gustaf's 15-Great Uncle. HM Harald V's 14-Great Uncle. `Red Baron' Richthofen's 13-Great Grandfather.