Poss. HM George I's 10-Great Grandfather. U.S. President [T. ROOSEVELT]'s 12-Great Grandfather. HRH Charles's 17-Great Grandfather. PM Churchill's 17-Great Grandfather. Lady Diana's 16-Great Grandfather. PM Cameron's 17-Great Grandfather. HRH Albert II's 18-Great Grandfather. Poss. Jamie's 16-Great Grandfather.