HRH Charles's 15-Great Grandmother. PM Cameron's 16-Great Aunt. HRH Albert II's 17-Great Aunt. HM Juan Carlos' 14-Great Aunt. Philippe of Belgium's 16-Great Grandmother. HM Manuel II's 14-Great Aunt. Grand Duke Henri's 16-Great Grandmother. HM Margrethe II's 15-Great Grandmother. HM Constantine II's 15-Great Grandmother. HM Carl XVI Gustaf's 15-Great Grandmother. HM Harald V's 15-Great Grandmother. Ksr Wilhelm II's 12-Great Aunt.