YOU SAID:
History will FORGET that a country ever existed in this area
INTO JAPANESE
歴史は、この地域に国が存在したことを忘れてしまいます
BACK INTO ENGLISH
History forgets that a country existed in this area
INTO JAPANESE
歴史はこの地域に国が存在したことを忘れています
BACK INTO ENGLISH
History forgets that a country existed in this area
That didn't even make that much sense in English.