Name the four major historical figures in the movie Amistad (1997).Not the stars who portrayed them

The answer to this depends to some extent on who you see
as a "major" historical figure and who is just a minor
figure.

There are two people portrayed in the film who are
clearly major historical figures, at least in the United States.  These are the two
presidents who are portrayed in the film.  They are Martin Van Buren and John Quincy
Adams.

Past that, it is less clear who is a major
historical figure.  Queen Isabella II of Spain is seen in the movie.  So is the
important abolitionist figure Lewis Tappan.  Roger Sherman Baldwin was a governor and a
US Senator.  Cinque himself can be seen as a major historical figure because of his role
in the Amistad incident.

You will need to decide for
yourself which of these people are "major" figures in history.