This film is based on real life events during the reign of King James I of Aragon. Unlike in other parts of Spain which were either controlled by the Muslim Moors or other Christian kinds, James seemed to want to have an open discussion and debate between an esteemed Jewish rabbi and a Christian convert...and as such, he promised no retributions against the Jews no matter the outcome. This is important because many prior Disputations resulted in increased persecution of the Jews. So, on July 20-24, 1263, a series of debates or 'disputations' occurred...and both sides claimed victory.
This film is a dramatization of the events and comes off more like a play than a movie. This is not a complaint...just a description of the style. The best thing about this movie aren't sets anyway...but the fine acting. This is particularly true in a most unusual performance by Christopher Lee....and because of this, it's well worth seeing...to see excellent acting with a minimum of accoutrements other than costumes.