 Octavian (who later became the emperor Augustus) convinced the Senate via a propaganda campaign to start a war against Cleopatra, since they were reluctant to declare war on Antony, as he was a true Roman and the last thing Octavian or the Senate needed was a mutiny.Eventually, Octavian chased Antony’s senatorial supporters from Rome, and in 32 BC, the Roman Senate declared war against Cleopatra.The Caesarians Octavian (Caesar's principal, though not sole, heir), Mark Antony, and Marcus Lepidus under the Second Triumvirate had stepped in to fill the power vacuum caused by Julius Caesar's assassination.