HRH Charles's 9-Great Grandfather. Philippe of Belgium's 10-Great Grandfather. Grand Duke Henri's 10-Great Grandfather. HM Margrethe II's 9-Great Grandfather. HM Constantine II's 9-Great Grandfather. HM Carl XVI Gustaf's 9-Great Grandfather. HM Harald V's 9-Great Grandfather. `Red Baron' Richthofen's 12-Great Uncle.