During his speech, Mark Antony skillfully manipulates the crowd by appealing to their emotions, and uses various rhetorical devices, including repetition, to emphasize his points. He skillfully turns the crowd's anger toward the conspirators, particularly Brutus and Cassius. As a result of Antony's speech, the Roman people become swayed and turn against the conspirators.
As the play unfolds, this shift in public opinion plays a crucial role in the downfall of Brutus and Cassius. They realize that they have underestimated Mark Antony's intelligence and persuasive abilities. Ultimately, Brutus and Cassius are defeated in battle and die.