Aeschylus is primarily concerned with the nature of justice. In the trilogy The Oresteia, the Akhaians evolve from an older, more primitive autocratic form of justice, to a new concept of civil justice devised by Athena. He confronts the contrast between the old and new orders, the lives of the members of the House of Atreus, and the serious moral questions that Orestes’ crime presents.
The case against Orestes is strong. The son admits to striking down his mother, in violation of the sacred tenant of kinship. "But I came back, my years of exile weathered—killed the one who bore me, I won’t deny it, killed her in revenge." (Eumenides lines 476-478) This shows that Orestes was fully aware of the act he was committing, that he willfully committed it, and that he must suffer for it. The bond between mother and child was broken when Orestes murdered Clytaemnestra. Marriage, arguably, is a tenant of Zeus and the Olympians. In the old order of things, family is by blood only. A husband and wife have no blood relation, yet the son is of the same blood as his parents. The Furies right to vengeance cannot be dismissed.
Clytaemnestra is one who upheld the laws of the Furies. Agamemnon’s murder of Iphegenia at Aulis was pure outrage. "Yes he had the heart to sacrifice his daughter , to bless the war…" (Agamemnon lines 222-223) Agamemnon killed his own blood relation in order to sail for Troy. This too, is a terrible crime, seemingly of the same weight as Orestes’ act. Clytaemnestra believed she was justified in avenging her daughter, because her husband violated a sacred tenant of the old gods. "Here is Agamemnon, my husband made a corpse by this right hand—a masterpiece of justice. Done is done." (Agamemnon lines 1429-1431) This shows a clear morality behind Clytaemnestra’s motives. She appears to have justification for her actions. The curse on the House of Atreus is fulfilled. In the last lines of Agamemnon the chorus foreshadows Orestes’ return. Clytaemnestra responds by saying to her new husband, "We will set the house in order once for all." (Agamemnon lines 1708) The chorus’s purpose for suggesting Orestes’s return is to show that the house is not yet cleansed of the curse..
Like his mother, Orestes possesses what he believes to be a just motive for revenge. Unlike his mother, however, Orestes has reservations about killing. He does not wish to strike down his mother, but realises that he must. The defense of Orestes is rooted in the fact that Apollo ordered him to do so. Orestes trusts Apollo’s guidance at his trial. "Apollo will never fail me, no, his tremendous power, his oracle charges me to see this trial through." (Libation Bearers lines 273-275) Orestes believes that he is justified in avenging his god-honoured father, who was so brutally murdered by his mother. This cycle of blood in the House of Atreus appears as if it will continue forever.
This cycle of violence leads the gods to search for a different solution. If the society of Greece is to progress to a higher civilisation, some other way must be found to resolve the conflict of moral questions. The ancient idea of vengeance doesn’t properly apply here because both Clytaemnestra and Orestes acted in support of legitimate definitions of justice. The ancient gods support Clytaemnestra and her actions, while Zeus, by means of Apollo, supports Orestes. The clash between deities sets the stage for the emergence of a new form of justice—civil justice.
The ancient law of retaliation, which states that blood must be paid for with more blood, is enforced by the Furies. This task was given to them by Destiny at the dawn of time. "…you’ll give me blood for blood, you must!… Wither you alive, drag you down and there you pay, agony for mother-killing agony!" (Eumenides lines 262, 265) Their concept of justice is one where the law of retaliation is applied absolutely. They have no notion of compassion or understanding. They uphold the belief that regardless of circumstances, Orestes must be made to pay for his crime of matricide. The Furies represent something older and more sacred which Apollo and Zeus do not respect.
Athena’s establishment of the court to try manslaughter is significant, because it provides