In Act One, Scene Two of Romeo and Juliet, several major complications of plot unfold, both resulting in the same outcome.
First, Lord Capulet discusses Paris' intentions of marrying Capulet's daughter, Juliet. Lord Capulet knows that Juliet is not even fourteen years old yet (and, thus, too young to be a wife); however, he also knows that Paris would be a good match for Juliet due to the fact that he is a wealthy kinsman of the Prince. Still, he realizes that "too soon marred are those so early made" and that his own approval is not enough to seal the deal. Juliet must be willing to become Paris' wife. Thus, Lord Capulet invites Paris to the masquerade ball that he will be having that evening in order to give Paris the opportunity to woo the girl. Of course, as we will soon discover, this also gives Romeo and Juliet the opportunity to meet!
Second, Romeo is still pining over his unrequited love for Rosaline when a messenger asks him to read a list of names out loud to him—the names of those who are being invited by Capulet to the aforementioned ball. Discovering that Rosaline is on this list of attendees, Romeo and friends decide to go to the ball, disguising themselves in order to hide the fact that they are Montagues. Again, this plot complication is what will lead to the chance meeting of the story's star-crossed lovers!