Actually, The Movie "A Knight's Tale" is directly based on Chaucer's "The Knight's Tale". In both stories, the two main characters go to tournament over one girl. However, there are conflicting details, that is the overall story of both tales.  

 Now if you wish to search further into the subject, one could say that the movie is a story of the making of The Canterbury Tales. In the movie, Chaucer comes into contact with a great variety of people of medieval society and in the end of the movie he states that he's going to write the story, "All human activity lies within the artist's scope" which is an allusion to the writing of the Canterbury Tales. There are all sorts of allusions like this one throughout the movie, you just have to know what to look for. 

 Anonymous 11:28 AM, 11 Dec 2005