Poss. HM George I's 28-Great Grandmother. U.S. President [WASHINGTON]'s 14-Great Grandmother. HRH Charles's 20-Great Grandmother. PM Churchill's 18-Great Grandmother. Lady Diana's 19-Great Grandmother. PM Cameron's 20-Great Grandmother. HRH Albert II's 21-Great Grandmother. `Osawatomie' Brown's 22-Great Grandmother. Jamie's 21-Great Grandmother.