With the last of the assassins taken care of, the Triumvirate got around to the serious business of re-assigning the spoils of war. Antony got the richer Eastern provinces (because he won—not that he rubbed that in or anything) and Southern France. Octavian slunk back to Italy with his tail between his legs with the veterans, but as a consolation prize he was given Spain (and Cisalpine Gaul was merged into Italy because there were just too many Gauls). Lepidus the easily forgotten got Africa and was quite happy with it too. Fortunately, before the triumvirate had time to get bored, a new enemy reared his ugly head: Sextus Pompey.
Sextus Pompey was the youngest son of Pompey the Great (remember him? He got the elephant stuck in the gate.) and grew up fighting the resistance against Caesar. When Caesar died, he was a bit at a loss of who to resist next, but when Octavian stepped up to the plate, he was more than happy to oblige. He got his best armies ready only to have to wait while the triumvirate chased Brutus and Cassius around. Then they were gone and he was ready once again. Only Antony’s brother Lucius decides to cause the Perusine War instead.
The Perusine War happened when Lucius who was a Consul grew tired of the unrest caused by proscriptions, confiscations, and the grain shortage caused by our man, Sextus in Rome. Since Octavian was out losing more battles (and probably getting all the good food which couldn’t make it around Sextus’s blockade) Lucius and Fulvia (Antony’s wife) decided to take matters into their own hands and took over Rome behind Octavian’s back. Besides, they didn’t like him too much anyway. This didn’t work out so well in the end as the troops came back and trapped them in the city of Perusia. In February they ran out of food (which put them right back where they started) and they had to surrender. Showing a masterly understanding of where the true responsibility for the uprising lay, Octavian spared both of their lives, then had the occupants of the city butchered. Furthermore, Lucius was sent to govern Spain—because it worked out real well last time he was left in charge. Fulvia was just exiled, but died a year later which was said to have brought peace between Octavian and Antony. I’m sure she would have been thrilled.
At long last, Sextus Pompey finally got his chance to square off against Octavian. Of course, Octavian’s first act was to marry Scribonia, a relation of Sextus, in the vain hope to just keep the fighting to the usual squabbles at holidays and reunions. While the marriage did provide him with his only child, Julia, it only lasted a year (he divorced her the same day Julia was born). It did, however, lead to the Misenum treaty in 39 BC where Sextus agreed to lift his blockade of Italy in exchange for Corsica, Sardinia, Sicily, and the Greek Peloponnesus. He was also promised a future consulship, priesthood, and money.
Somehow, it didn’t take. Octavian and Antony found they could only work together when working against someone else. Besides, they were greedy little bastards. In 38 BC Octavian tried to take back Sicily. He was defeated. In 37 BC he tried again. It didn’t work that time either. And don’t even ask about 36 BC. Octavian was a bit of a slow learner. Fortunately, his best general Agrippa wasn’t and he finally succeeded in defeating Sextus and harrying him around the globe. In 35 BC, Sextus was finally caught by one of Antony’s minions and executed without a trial. It marked the end of an error. From now on, Antony and Octavian would have no one to fight but each other.