The Agamemnon, by Aeschylus, forms the opening third of the lone Greek trilogy to survive till this day; the Oresteia. The play explores the reasons for the death of Agamemnon, a Trojan general who despite returning victorious from Troy finds himself surrounded with animosity on his homecoming. However, Aeschylus maneuvers the original legend in order to stress the hazards associated with power. Unlike the Homeric myths, however, Aeschylus does not outwardly suggest that Agamemnon's death was as a result of Clytemnestra's seemingly endless desire for power, but in fact there were a range of underlying reasons for Agamemnon's murder.
The first reason, and probably the most significant reason offered for the death of Agamemnon was the sacrifice of Iphigenia. The Achaean forces were unable to sail due to the winds which had been stopped by the will of Artemis. The seer Calchas found the apparent solution when he recommended Agamemnon sacrifice his daughter Iphigenia. By doing so, not only would they sail to Troy, but they would sack the city. If they did not, they would not be able to sail. It is one of the major reasons Clytemnestra puts forward for her murder of her husband. She immediately challenges the chorus, who never openly condemned the murder of Iphegina, yet condemn Clytemnestra for her actions.
The household itself is generally associated with ill feeling and treachery. As the watchman notes at the start, there is something wrong with the home. Although for generations the house has been the scene of evil deeds, the deeds of Agamemnon's and Menelaus father, Atreus are the actions that will dominate the background of the play. After learning of Thyestes adultery with his wife Aerope, Atreus killed Thyestes sons, save their hands and feet, and served them to Thyestes. Thereafter Thyestes consulted an oracle, who advised him that if he had a son by his daughter, he would slay Atreus.
The child was Aigisthus, who was abandoned by his ashamed mother and was given to Atreus by a shepherd. As he entered adolescence, Thyestes revealed the truth of his origin to him, and he killed Atreus, although not before Atreus had fathered two children, Menelaus and Agamemnon. Therein lies Aigisthus' reason for the murder of Agamemnon - to wipe the away the seed of the evil Atreus who wronged his father and siblings.
However, Aigisthus is given a very effeminate role in proceedings. He is seen in the background, and does not murder Agamemnon himself. Rather, he relies on Clytemnestra to take centre stage. This is in stark contrast to the Homeric myth, where Clytemnestra is presented as little more than a woman who gives into her weaknesses and Aigisthus is presented as the evil usurper who grabs his opportunity to take over the city of Argos and plans the downfall of Agamemnon. He is often at odds with the Chorus who are not very fond of him and by the end of the play he is little more than a puppet in the sinister hands of Clytemnestra.