In Rome, at the house of Octavius, Octavius complains to Maecenas and Agrippa about Antony’s behavior: he has enthroned Cleopatra and himself in public on a platform of silver with golden chairs, and has declared Cleopatra queen of Egypt, Syria, Cyprus, and Lydia. Moreover, he has declared his sons by Cleopatra “the kings of kings.” Antony has also publicly accused Octavius of denying his rightful share of the spoils from recently defeating Pompey (including part of Sicily). Octavius says that he will only give Antony his share if Antony gives him part of the conquered territories of Armenia.
Octavius is furious both at Antony’s apparent betrayal of Rome (by establishing a kingdom in Egypt) and his extravagant decadence, exemplified by the golden chairs. The two are squabbling over the division of territories and spoils, but their quarrel will soon turn into an open military conflict.
Octavia arrives and Octavius marvels that she came to Rome secretly, without any entourage. She tells him that she has come to beg pardon for Antony. He asks her if she knows where Antony is, and she says he is in Athens. He informs her that Antony has betrayed her, and is actually in Egypt with Cleopatra. Octavius says that Antony “hath given his empire / Up to a whore,” and has assembled allies for war.
Octavia has come as a messenger from Antony, but Octavius is the one who has news for her. Antony has betrayed Octavia and his oath of marital fidelity in order to cavort with Cleopatra in Egypt, because he never really loved Octavia and can't keep himself from Cleopatra.
Octavia is shocked, and laments that she has her “heart parted betwixt two friends.” Octavius says that he held off on fighting with Antony for her sake, until he learned that Antony had wronged her. He welcomes her to Rome and encourages her to stay. Maecenas tells her that everyone in Rome loves and pities her.
As a foil to the strong, manipulative Cleopatra, Octavia is very passive, and is under the care and control of the men in her life, whether Antony or Octavius.