Question

What is one of the main differences between the conspirators and the triumvirates?

Answer 1

Just as Act III ends, right after Antony's funeral speech, Rome erupts into a chaotic, mob-led brawl.  The people have been so inflamed by Antony's speech and the murder of Caesar, that chaos reigns and the country is on the brink of a civil war.

Act IV, by contrast, opens in what appears to be a calm and controlled meeting of the three men who will become Rome's second triumvirate of rulers:  Marc Antony, Octavius.