Shakespeare's audience already knew the essential story of Romeo and Juliet, a popular story in European folklore which Arthur Brooke had translated into English in 1562 as a poem called The Tragicall Historye of Romeus and Juliet. Brooke based his poem on Pierre Boaistuau's French translation of the story from Italian sources in 1559.
Shakespeare adapts Brooke's poem for the stage, developing the characters, condensing the timeframe, and adding certain scenes to underscore his own themes. For example, Shakespeare reduces Juliet's age from 16 to 13 to emphasize her youth and vulnerability. Shakespeare expands Mercutio's role by adding the scenes in which Mercutio gives his Queen Mab speech and meets the Nurse. Shakespeare also develops the scene in which Romeo kills Tybalt: First, Mercutio accepts Tybalt's challenge on Romeo's behalf, and then Tybalt kills Mercutio under Romeo's arm as he tries to part the two men. In Brooke, Romeo kills Tybalt in self-defense, but Shakespeare shifts the emphasis so that Romeo is forced to take revenge for his friend's death by killing Tybalt.
Shakespeare compresses the action from months, as it appears in Brooke, to just over four days. In Brooke, Romeo and Juliet have been married nearly three months before Tybalt's death brings about their separation. In Shakespeare's play, Romeo and Juliet's wedding occurs on the same day as Romeo's banishment, so that the lovers are only able to spend a single night together. Shakespeare also develops the plot by adding the scene in which Capulet brings the wedding forward from Thursday to Wednesday. These developments are used to indicate the speed with which Romeo and Juliet rush headlong into love, while creating intense pressure as events conspire to bring the lovers to their tragic deaths.
