Antony might not have been so angry if Octavius Caesar's struggle with Sextus Pompeius had gone badly for the former. The situation had changed from what it was before, however. When Sextus closed off Rome's life line he found out why Menas had been opposed to the compromise agreement at Misenum. Octavius had used the respite to stock Rome and to fill its storehouses. It would take a long time before it could be choked once more and meanwhile Octavius could strike back. Sextus found that while Antony and Octavius could easily undo their part of the agreement, he could not undo his; he could not withdraw the food he had allowed into Rome.
It was still necessary to fight Sextus, however, even if Rome was not starving. Octavius Caesar twice sent out ships to fight Sextus, and twice Sextus' hardened sea fighters won.
Octavius Caesar therefore set to work in earnest. He placed Agrippa in charge and ordered
Antony's impulse, then, is to engage in open hostilities, now, while Sextus can still be his ally and while Octavius is still without real power at sea. (Antony himself can always have the Egyptian fleet at his disposal, in addition to his own ships.)
Now conies time for the purpose of the marriage of Octavia to show itself. Octavia pleads for peace between husband and brother and urges Antony to let her serve as peacemaker. Antony agrees, saying:
—Act III, scene iv, lines 24-27
Octavia may try to make the peace, then, but if she fails, Antony will make war. Actually, she succeeded. She met her brother and managed to arrange another meeting between Antony and Octavius Caesar at Tarentum in southern Italy in 37 b.c. Peace between them continued.
So much the worse for Antony, however, and the marriage with Octavia proved a disaster for him. The peace she arranged was one in which Antony agreed to, and did, suspend his preparations for war; and in which Octavius Caesar agreed to, but did not, suspend his own preparations for sea mastery. In the interval of peace between the triumvirs, Octavius Caesar continued to build his fleet
Shakespeare skips this second reconciliation altogether. Immediately after the scene with Octavia in which she is sent off as mediator, Enobarbus and another of Antony's captains, Eros, rush in to discuss military matters. Eros has news, and says:
—Act III, scene v, lines 4-5
This sounds like the same wars that Antony has been complaining about in the previous scene, especially since Enobarbus responds by saying:
—Act III, scene v, line 6
Actually, it is a new war, begun after Octavia has brought about the meeting at Tarentum and the reconciliation.
On July 1, 36 b.c., Agrippa's new fleet set out in three squadrons, Agrippa at the head of one, Octavius of a second, and Lepidus of a third. For two months these ships and those of Sextus met, with victory usually resting with Sextus. At one point, Octavius' squadron was nearly wiped out.
Finally, on September 3, 36 B.C., Sextus was forced to accept battle with Agrippa near the Strait of Messina, which separates Sicily and Italy. This time Sextus was defeated by sea and land, and his power was utterly destroyed. He managed to get away himself and fled eastward, hoping to find safety with Antony.
Antony could now see into what catastrophe Octavia's mediation had led him. Octavius Caesar had beaten Sextus and Antony had lost his chance to make vigorous war against Octavius in combination with Sextus. Making that same war without Sextus and with Octavius equipped now with a victorious navy was another, and worse, matter altogether.
Nor was this the full extent to which matters had turned against Antony. Eros has more news, about Lepidus:
—Act III, scene v, lines 7-13
What happened was that after Sextus Pompeius was defeated, Octavius Caesar added all the conquered areas (Sicily, Sardinia, Corsica, and so on) to the provinces controlled by himself. Lepidus, who controlled only Africa, felt that since he had shared in the fighting, he ought to get some of the loot. This Octavius Caesar refused ("would not let him partake in the glory of the action").
Lepidus attempted to use force but this Octavius Caesar scotched at once. He entered Lepidus' camp with a small body of troops, sure that Lepidus' portion of the army would not support their general (probably he had made arrangements with Lepidus' troops in advance). He was right. Lepidus' men deserted him.
Lepidus was therefore demoted from his triumviral status and Africa was taken from him. He was not imprisoned, however, for he was not that dangerous. He was sent back to Rome and was allowed to keep the purely honorary title of Pontifex Maximus ("high priest"), in which role he had many harmless duties to perform. He kept the job for the remaining quarter century of his life and never bothered anyone again.
Octavius Caesar is now without a rival in the West. He rules all the provinces and is stronger than ever before. Antony, who had lost his chance for effective military action, can now only rage. Eros describes his actions:
—Act III, scene v, lines 17-20
Sextus Pompeius, fleeing from the lost battle near Sicily, had gone first to the Aegean island of Lesbos, and then to Asia Minor. There he had been taken by a contingent of Antony's troops, and the officer in charge, assuming him to be an enemy, killed him. That was the end of Sextus Pompeius, just three years after he might have been the lord of all the world by merely cutting a hawser first and then three throats.