Palamon and Arcite are rivals for the love of the same woman. The knights decide to fight a duel to determine who gets her. Yet when Duke Theseus stumbles upon the dueling knights, he declares their fight is unlawful. The Duke proposes instead that there be a public joust, with a very clear set of rules, and the winner will marry Emily. Whereas the knight's duel upset the order of Theseus's kingdom, the joust becomes a part of it, showing the way in which violent competition can both disrupt and reinforce the rules of a society. One important rule that the competition enforces is that a single noblewoman must marry. Emily is the "prize" in this game whether she likes it or not, just as her sister, Hippolyta, was Theseus's prize after defeating the Amazons. In "The Knight's Tale," then, a man's job is to compete, while a women's role is to reward the winner.
Theseus proposes the joust between Palamon and Arcite as a way for him to measure the strength of a potential ally.
"The Knight's Tale" portrays public competition as a valid way to decide disputes, whereas private, un-refereed duels are not.