Antony and Octavian
While the conspirators fled Rome, and later Italy, the factio was left in confusion. One of them, the competent general and Consul Mark Antony, became temporary leader of the group, acting as Caesar’s heir. Marcus Aemilius Lepidus, another prominent member of the factio, intended to subdue the unrest in Rome by force, but was restrained by Antony. Instead, he reached a compromise with the Senate, declaring that Caesar's legislative initiatives would stand in exchange for a pardon to the conspirators.
However, despite this peaceful resolution, things were not so simple. Not only was Antony now illegally seeking governorship of regions in Gaul that would give him some political weight to throw at the Senate, but Caesar’s will had listed his grand-nephew Gaius Octavius, known as Octavian, as heir to his personal fortune and social position. Only 19 at the time and currently doing military training elsewhere, he returned to Rome as soon as he heard of Caesar's death, collecting supporters among veterans of Caesar’s legions along the way. The Senate, spurred on by Cicero’s Philippics, which accused Antony of seeking absolute power, granted Octavian the role of propraetor in Cisalpine Gaul and two legions. Octavian would then ally with the current proconsul of the region, Decimus Brutus (cousin to the conspirator Brutus), to defeat Antony in battle, forcing him to retreat.
The Rise of the Second Triumvirate
At this point, Octavian began to break from the Senate due to their refusal fulfill financial promises and name him consul, only granting him the role of praetor. In response, Octavian marched on Rome with eight legions. Through the support of the masses and a veteran-based army, as well as military friends such as Agrippa and Maecenas, he was able to force his election as consul. Meanwhile, Lepidus allied with Antony, and senatorial control of the western provinces collapsed. Surprisingly, Octavian, wishing to avenge Caesar, assure his own power, and restore stability to Rome, allied with the two men under the Second Triumvirate. This three-man dictatorship was able to pass laws, appoint all higher magistrates, conscript limitless numbers of soldiers, tax the populace, and pursue military actions. It also marked the definitive end of the Roman Republic.
Civil Wars Under the Triumvirate
They began their rule by massacring their political enemies, about 300 senators and 2,000 equites, including Cicero, and confiscated their properties in order to pay off soldiers and factio supporters. Their next targets were the conspirators Cassius and Brutus, who had been given proconsulships in Macedonia and Syria, respectively. By 43 BCE, the two had taken over all of Asia Minor and other Eastern provinces, as well as obtaining the allegiances of rulers such as Cleopatra. Planning to stamp out the rest of the liberatores, Antony and Octavian combined forces and met their opponents at Philippi in Macedonia. In the first battle, Octavian was initially bested by Brutus, but Antony's troop defeated Cassius, who then committed suicide. Two weeks later, the factio ended all hopes of the conspirators by defeating Brutus, who took his own life as well.
The victors went on to divide the Roman lands between them. Before, Lepidus and Antony had controlled most of Gaul and Spain, while Octavian was awarded Italian Islands and Africa, with Italy being shared. After Philippi, however, Antony received most regions, with Lepidus falling out of favor. Antony then went to the east to fight against Parthia, and Octavian, in the meantime, disbanded the legions and settled veterans from both sides in Italy and southern Gaul. However, this was no easy task, as Octavian incurred the displeasure of Italian aristocrats whose lands were taken, among these being Antony’s wife Fulvia and his brother L. Antonius. The two encouraged armed opposition to Octavian, who, along with his colleague Agrippa, asserted his power and defeated the rebels at Perusia. In de facto terms, Octavian had thus taken control of the western Roman regions.