What is the significance of Octavius having the closing lines of William Shakespeare's play Julius Caesar?
William Shakespeare's play Julius Caesar covers the real events surrounding the end of the Roman Republic, being based primarily on historical material found in Thomas North's 1579 translation of Plutarch. Although some of the conspirators were motivated by power or jealousy, the most interesting and important of the group is Brutus, who is genuinely an honorable man. As Antony states:
All the conspirators save only he
Did that they did in envy of great Caesar;
He only, in a general honest thought
And common good to all, made one of them.
What makes Brutus such an interesting and complex character is that he personally liked and admired Julius Caesar, but felt that the very fact that Caesar was a good ruler made autocracy attractive. It was Caesar's very virtues that made him a threat to the Republic. Thus Brutus feels that the only way to preserve the Republic and avoid Rome falling under the sway of an autocrat is by joining the conspiracy to assassinate Julius Caesar.
In the wake of the assassination, rather than Rome reverting to a Republic, Octavius Caesar, Julius's nephew, takes the name Augustus and becomes emperor, a form of rule even more autocratic than his uncle's principate. Having Octavius end the play, even as he eulogizes Brutus, signifies the way in which Octavius also ended the hope of any restoration of the Republic, the very thing for which Brutus had sacrificed Caesar's life and his own.