HM George I's 15-Great Grandfather. U.S. President [T. ROOSEVELT]'s 20-Great Grandfather. PM Churchill's 21-Great Grandfather. Lady Diana's 23-Great Grandfather. PM Cameron's 24-Great Grandfather. Louis XVII's 19-Great Grandfather. Gen. Pierpont Hamilton's 20-Great Grandfather. Poss. Jamie's 23-Great Grandfather.