Poss. HM George I's 16-Great Grandfather. Poss. HRE Charles VI's 18-Great Grandfather. Poss. U.S. President [WASHINGTON]'s 21-Great Grandfather. Poss. PM Churchill's 24-Great Grandfather. Poss. Lady Diana's 24-Great Grandfather. Poss. PM Cameron's 26-Great Grandfather. Poss. Jamie's 28-Great Grandfather.