HRH Charles's 15-Great Grandfather. HM Juan Carlos' 14-Great Grandfather. Philippe of Belgium's 14-Great Grandfather. Grand Duke Henri's 14-Great Grandfather. HM Margrethe II's 14-Great Grandfather. HM Beatrix's 14-Great Grandfather. HM Constantine II's 15-Great Grandfather. HM Carl XVI Gustaf's 14-Great Grandfather. HM Harald V's 13-Great Grandfather. Ksr Wilhelm II's 13-Great Grandfather.