Probably written in 1599, Julius Caesar was the earliest of Shakespeare's three Roman history plays. Like Antony and Cleopatra and Coriolanus, Julius Caesar is a dramatization of actual events, Shakespeare drawing upon the ancient Roman historian Plutarch's Lives of Caesar, Brutus, and Mark Antony as the primary source of the play's plot and characters. The play is tightly structured. It establishes the dramatic problem of alarm at Julius Caesar's ambition to become "king" (or dictator) in the very first scene and introduces signs that Caesar must "beware the Ides of March" from the outset. Before its midpoint, Caesar is assassinated, and shortly after Mark Antony's famous funeral oration ("Friends, Romans, and countrymen … "), the setting shifts permanently from Rome to the battlefields on which Brutus and Cassius meet their inevitable defeat. Julius Caesar is also a tragedy; but despite its title, the tragic character of the play is Brutus, the noble Roman whose decision to take part in the conspiracy for the sake of freedom plunges him into a personal conflict and his country into civil war.

Literary scholars have debated for centuries about the question of who exactly is the protagonist of this play. The seemingly simple answer to this question would be Julius Caesar himself—after all, the play is named after him, and the events of the play all relate to him. However, Caesar only appears in three scenes (four if the ghost is included), thus apparently making him an unlikely choice for the protagonist who is supposed to be the main character. Meanwhile, Brutus, who is in the play much more often than Caesar (and actually lasts until the final scene), is not the title character of the play and is listed in the dramatis personae not only after Caesar but after the entire triumvirate and some senators who barely appear in the play. Determining the protagonist is