At the end of this play, Rome finally regains its order and peace. The war between the various major characters finally ends. In its place, Octavius and Antony become the two men who indisputably have the most power in Rome.
Through most of the play, there has been discord in Rome. The way that the play ends resolves much of this discord. Brutus and Cassius essentially both commit suicide. By doing this, they are paying for the discord that they have caused. Meanwhile, Octavius and Antony are trying to take actions that will reunite Rome. Octavius has his prisoners treated well, Antony speaks well of the dead Brutus.
So, at the end of the play, at least, there is harmony in Rome once again.