Lady Diana's 13-Great Grandfather. HM Juan Carlos' 13-Great Grandfather. Philippe of Belgium's 13-Great Grandfather. Grand Duke Henri's 13-Great Grandfather. HM Margrethe II's 13-Great Grandfather. HM Beatrix's 12-Great Grandfather. HM Constantine II's 13-Great Grandfather. HM Carl XVI Gustaf's 13-Great Grandfather. HM Harald V's 12-Great Grandfather.