Pocahontas: who wrote the screenplay?did they adapt it from a book, a play or did they create it themselves?

Pocahontas 
Who wrote the screenplay? Did they adapt it from a book, a play or did they create it
themselves?
What roles did historians play in making the movie?
Did the era in which the film was made impact the way it portrayed history? For example,
if it is a movie about war, were they trying to instill or glorify patriotism and duty or were
they trying to show the futility and horror of war? Or something else all together?
What was the director’s approach to portraying history?