Antony's soldiers stand guard before Cleopatra's palace; all of them are aware that this is the night before the final battle that shall determine Antony's fate. Suddenly they hear strange noises and eerie music, and one soldier claims that this is an ill omen from the god Hercules, from whom Antony is believed to be descended. The soldier fears that these events are a sign that the god no longer favors Antony. The soldiers attempt to follow the source of the music but cannot discover it.
Both classical and Elizabethan accounts of the Battle of Actium mention the occurrence of supernatural omens before the battle. Plutarch's version of these events varies considerably from Shakespeare's, but Shakespeare was establishing a sense of foreboding. It is also probable that Shakespeare inserted this scene to establish the importance of the final battle, which is, of course, the climax of the play; he often made use of supernatural omens to foretell a tragic death, as, for example, in Julius Caesar, Macbeth, and Hamlet. Historians writing before and after Shakespeare's time often referred to such events, so it is difficult to know whether they did so because they believed that these events really occurred or because they were ingredients for a good story. At any rate, this scene creates a tense feeling of suspense. Our attention is focused wholly on this final battle, the one that will determine the fates of Caesar, Antony, and Cleopatra.