Athene enters, followed by the twelve jurors and a herald. Other citizens of Athens assemble to observe the trial. Apollo comes in with Orestes and announces that he intends to assist the defendant. Athene calls the new court to order and invites the Furies, as plaintiffs, to begin the trial by presenting their case.
The chorus question Orestes. He admits having killed Clytaemestra but says that he was ordered to commit the crime by Apollo. He demands to know why the Furies did not punish Clytaemestra for the murder of Agamemnon. They reply that Clytaemestra has already been punished by her death at his hands. Besides, since Agamemnon was not her blood relation, his murder has no bearing on this case. Confused by the course his trial is taking, Orestes asks Apollo to speak for him. Orestes says that he willingly admits the murder but does not himself know whether he did right or wrong.
Apollo asserts that all the oracles he has ever spoken, whether pertaining to man, woman, or city, have been in accordance with the will of Zeus. The oracle by which he commanded Orestes to murder his mother was no exception and embodied the express wishes of Zeus. And, he warns the jurors, the will of Zeus has more force than the oaths they have taken to judge according to their own understanding of the case.
So in other words, the chorus remark, Zeus himself said that Orestes could murder his mother with impunity. Apollo ignores this and says that the death of Agamemnon is not to be compared with that of Clytaemestra, for Agamemnon was a great man and a king, and was killed by treachery ill-suited to his station in life.
The chorus reply that Apollo seems to be suggesting that Zeus regards the murder of a father as the most serious of crimes, yet Zeus himself bound his own father Cronos in chains. How can he reconcile these contradictions? This question makes Apollo violently angry, and he insults the Furies as "foul animals." He says that Zeus can undo the chains that bind Cronos and make good the harm that was done, but murder is final and can never be undone.
The chorus ask whether Apollo has considered how one who has shed his mother's blood, an act of absolute finality for which there is no atonement, can ever again return to his homeland or participate in religious rituals.
Apollo answers that the mother is not a blood relation of the child, but only the nurse of the seed planted in her by the true parent, the father. Thus Orestes has incurred no bloodguilt. As proof of this doctrine, Apollo cites Athene herself, for legend said that she was born full-grown from the forehead of her father, Zeus. Apollo concludes his speech by promising greatly to increase the wealth and power of Athens if Orestes is acquitted.
Athene turns the case over to the jurors for their decision and formally establishes this new tribunal — the Court of the Areopagus — to endure forever and to have jurisdiction in all cases of manslaughter. She advises the jurymen to judge and govern in justice and not to drive out fear from their city, for the man who fears nothing cannot be righteous. This court, she says, will be a shrine of justice, the greatest strength of her holy city. Nothing will corrupt it. As "a sentry on the land," it will forever protect the innocent and punish the guilty. She urges the jurors to meditate on the meaning of their oaths and arrive at a decision.
The Furies and Apollo threaten the jurors with reprisals if they lose the case, then begin to bicker with each other. Meanwhile, Athene announces that in the event of a tie, she will cast her vote in favor of Orestes. She says this is because she had no mother and thus must support the rights of the father, and also because she likes men, although not enough to marry one.
The jurors cast their votes. There are six for conviction, six for acquittal. Athene votes for acquittal also and Orestes is declared a free man. The former defendant joyfully thanks Athene and solemnly vows that for all time the people of Argos, his homeland, will be the friends and allies of the Athenians. He wishes the best of success and fortune to Athens, then leaves with Apollo.
Since one purpose of this scene is to give the prestige of divine sanction to the legal processes in Athens, this trial has many similarities to the way in which trials were actually conducted in the time of Aeschylus. Among these similarities are the preliminary hearing to determine jurisdiction, the privilege of the accused to speak last, the rule that the accused be acquitted if the votes of the jurors are equal, the repeated exhortations to the jurors to remember their oaths, and the right of the plaintiff to prosecute his own case. The ancient homicide court of the Areopagus was one of the most revered legal institutions in fifth century Athens. The interesting account of its origin given by Aeschylus must have made his complex story seem particularly pertinent in the eyes of his audience.
Apollo acts as the advocate of Orestes at the trial, but the defense he presents is far from adequate. This is because the Furies, despite their primitive nature, protect sacred bonds of kinship and blood that cannot be ignored. Although he is a god, Apollo cannot negate their position because it is an essential constituent of an ordered society. His arguments for Orestes have been made weak to emphasize that neither side in this dispute is entirely right.
In his first speech, Apollo tries to influence the jurors by an appeal to authority rather than to reason. By including oracles pertaining to cities in his claim always to have expressed the will of Zeus, Apollo puts his political and moral oracles on a par. The Delphic oracle was notorious for having made some serious mistakes in political matters, most particularly when it opposed resistance to the Persian invasion. The jurors are bound to wonder whether Apollo's morality may not be as subject to error as his politics.
In his second speech, Apollo attacks Clytaemestra for killing Agamemnon by treachery, but Orestes killed Clytaemestra by treachery also and did so in accordance with Apollo's own command. In addition, Apollo implies that there is no difference between matricide and any other form of murder, a view that would probably offend the jurors. While describing Agamemnon's greatness in life, Apollo inadvertently alludes to the sacrifice of Iphigenia, an incident bound to increase sympathy for Clytaemestra at a moment when he is trying to emphasize her wickedness.
Apollo's third speech is weak because the murder of a woman is as final as that of a man. The theory of parenthood presented in Apollo's final speech is farfetched and denies the intimate emotional bond between mothers and their sons, another point that might offend the jurors. Finally, Apollo concludes with a shameless offer to bribe the jurors if they vote in favor of Orestes.
The case presented by Apollo is so unsatisfactory that it would appear Aeschylus used the framework of a debate as the basis for a dramatic confrontation between adversaries and made no real effort at a well-reasoned analysis of the particular case under discussion. The reason for this is made clear when the jurors vote. They are tied because the case is too hard for human beings to judge. There is justice on both sides — neither the ties of kinship nor the requirements of authority and the social order can be denied. Athene casts the deciding vote as the first step in the establishment of a new and greater social and moral order in which the desirable elements of the views represented by the Furies and the Olympian gods are combined. It is interesting to note that Athene's reason for voting to acquit Orestes is morally irrelevant to the issue on trial, a final reminder that there can be no arbitrary solutions to moral problems.
The trial of Orestes is important in dramatic history because it is the first extended scene in which three speaking actors and the chorus (here actually used as a fourth speaking actor) all take important parts in the action at once. There is a difficult transition at the end of the scene where Orestes and Apollo drop out of the action before the conclusion of the play, but Aeschylus handles this effectively by giving emphasis to the dissatisfaction and threats of the chorus and letting these carry over into the next episode.