HM George I's 8-Great Grandfather. HRE Charles VI's 10-Great Grandfather. PM Churchill's 16-Great Grandfather. Lady Diana's 17-Great Grandfather. PM Cameron's 17-Great Grandfather. HRH Albert II's 17-Great Grandfather. HM Margrethe II's 15-Great Grandfather. `Red Baron' Richthofen's 13-Great Grandfather.