Aegisthus was the cousin of Agamemnon and Menelaus. While Agamemnon was occupied in Troy, Aegisthus usurped the rule of his kingdom and slept with his wife, Clytaemnestra. When Agamemnon returned from war, it was to find the two lying in wait, plotting his death. As Zeus mentions in this speech, Orestes, son of Agamemnon, grew up to avenge his father’s death. This story is just one small piece of a larger web of suffering and destruction spun around the House of Atreus.
Homer will use the death of Agamemnon and the revenge of Orestes as a recurring theme throughout The Odyssey. The figure of Clytaemnestra as scheming, adulterant murderess, contrasts powerfully with the character of Penelope, the faithful, enduring wife. Orestes also represents a model of filial piety for Telemachus to imitate. Telemachus, it is implied, should take Orestes’ example to heart in his dealings with the arrogant Suitors.