He is in on the murder plot as well, as a way to avenge his brothers, who had been not only slaughtered by Agamemnon’s father, Atreus, but also cooked and served as dinner to Aegisthus’ father, Thyestes. However, that’s not the whole story, as we soon learn from Clytemnestra’s lover (and Agamemnon’s cousin) Aegisthus, who unexpectedly appears on stage. Indeed, it is: Clytemnestra murders both Agamemnon and his lover, and defends this decision before the Chorus as a just act of revenge for Agamemnon having sacrificed their daughter, Iphigenia, to appease the gods for a transgression of his own – namely, killing Artemis’ sacred deer.

Even so, she decides to enter the palace as well, believing this to be her inevitable fate. Left behind, Cassandra, a prophetess cursed not to be believed by anyone, senses this outcome. It is a hubristic act, with which Clytemnestra tries to give further justification to what she intends to do next: murder Agamemnon.

Regardless of this, Clytemnestra welcomes her husband gushingly, eventually even persuading him to enter his palace by treading over a purple tapestry more becoming for gods than humans. The information is subsequently confirmed by a Herald, soon after which Agamemnon arrives in a chariot that also carries Cassandra, the Trojan princess, a spoil of war and a new bedmate of Agamemnon. The play is set in front of the palace of Argos and begins with a Watcher noticing a beacon fire which signals the return of Argos’ king, Agamemnon, ten years after sailing away to conquer Troy.

Originally performed in 458 BC, Agamemnonis the first play in Aeschylus' Oresteia trilogy, which also includes Libation Bearers and Eumenides.

The oresteia of aeschylus agamemnon