The audience is now prepared for the third play in the trilogy, The Eumenides. Aeschylus has prepared the way in the first two plays for a necessary resolution of some kind. Either Orestes must be punished for matricide, thus preserving the old blood way, or a new, more reasonable set of rules or laws must be established, more in keeping with the reality of the city-state represented by the audience. It must be remembered that the plays of the City Dionysia were cathartic ritual dramas meant to purge the city itself. The heroes on the stage suffer and the audience with them, but order is eventually established and life can go on in a better way.

As The Eumenides opens, Orestes is being plagued by the Furies. He flees to Delphi, seeking Apollo’s help. Apollo has supported his revenge killings but even he cannot overpower the Furies. He does cast a spell on them, however, causing them to sleep while Orestes continues on to Athens, protected by Hermes. In a terrifying scene, Clytemnestra’s ghost appears to the Eumenides and urges them to pursue Orestes. They wake up and search for Orestes’ tracks by gathering the scent of the blood of Clytemnestra on his feet. When they find him in Athens, he is holding on to a statue of Athene. As the Furies surround him, Athene intervenes. She calls for a trial. There will be a jury of twelve, of which she will be one. Apollo will represent Orestes, the Eumenides will represent the dead Clytemnestra. In the trial, Apollo argues that in a marriage the man is more important than the woman (Athens was a patriarchal society, so the audience of men would have agreed). In support of the concept of male dominance, he points out that Athene herself had been born of Zeus’s head rather than of a mother. Therefore, Clytemnestra’s crime is greater than her son’s, whose act of vengeance was justified. Athene and five others vote for acquittal, meaning the jury is evenly split. Because Athene at the beginning had stipulated that a tied jury meant acquittal, Orestes is acquitted. The Furies are “furious,” but Athene convinces them that a new precedent—a reasonable and wise law of Apollo and Athene—has been established, a law which, of course, reflected Athenian law as opposed to the blood-for-blood law of the old days. The Eumenides are given a new home and are renamed “The Venerable Ones.” They will now guarantee the prosperity of Athens, a city based on the understanding that mercy takes precedence over blood revenge.

Not surprisingly, when The Oresteia trilogy was performed at the City Dionysia in 458 B.C.E., it won first prize.