It was fated that Thyestes should live to father upon his own daughter a son, Aegisthus, who would slay Atreus and bring ruin and death upon Agamemnon.

But his wife Clytemnestra, enraged at Agamemnon because he had sacrificed her daughter Iphigenia at Aulis to appease the winds, and full of jealousy because he brings Cassandra as her rival home, estranged also by the long-continued absence of her husband, but most estranged by her own guilty affair with Aegisthus, is now plotting to slay her husband on his return, gaining both revenge and safety from his anger.

The Chorus of the Women of Argos or Mycenae complains of exalted fortune as unstable, full of anxieties and cares, and therefore gives preference to a modest life.

[2] Clytemnestra, conscious of her own wickedness, and fearing punishment for her adultery now that her husband has just returned, meditates the destruction of Agamemnon as a remedy.

The chorus of the women of Mycenae and Argos sing a triumphal hymn in honor of Apollo on account of the victory gained at Troy, but introduce laudatory addresses to Juno, Minerva and Jupiter.

[4] Other (lost) plays which might have influenced Seneca include Agamemnon by Ion of Chios, Aegisthus by Livius Andronicus, and Clytemnestra by Accius.