Poss. HRH Charles's 12-Great Grandfather. Poss. PM Cameron's 14-Great Grandfather. Poss. HRH Albert II's 15-Great Grandfather. Poss. HM Juan Carlos' 12-Great Grandfather. Poss. Philippe of Belgium's 13-Great Grandfather. Poss. HM Manuel II's 12-Great Grandfather. Poss. Ksr Wilhelm II's 10-Great Grandfather.