Prester John
/ˈprestə(r)/- a legendary medieval Christian king of Asia, said to have defeated the Muslims and to be destined to bring help to the Holy Land祭司王约翰（传说中的中世纪亚洲基督徒国王, 据说曾打败过穆斯林并预定要援助圣地）。
词源
Middle English: from Old French prestre Jehan, from medieval Latin presbyter Johannes 'priest John'.