Poss. HM George I's 10-Great Grandmother. Poss. HRE Charles VI's 12-Great Grandmother. Poss. U.S. President [WASHINGTON]'s 15-Great Grandmother. Poss. PM Churchill's 20-Great Grandmother. Poss. Lady Diana's 19-Great Grandmother. Poss. PM Cameron's 19-Great Grandmother. Poss. Jamie's 22-Great Grandmother.