Athena reenters with the jurors she has selected for the trial (perhaps 11 in number, made up of silent extras). She is accompanied by a Herald, whom she orders to gather the assembly with his trumpet so that the proceedings can begin. Apollo enters. Accepting his responsibility for Orestes’s actions, he declares that he will act as the advocate for the defense. Athena, announcing the trial opened, tells the Furies, as the prosecution, to make their case first. The Furies interrogate Orestes, who confesses to having killed his mother following Apollo’s instruction to punish her for her murder of his father Agamemnon. He questions, however, whether shedding his mother’s blood should be understood as kindred bloodshed and calls on Apollo to make the case for the justice of his actions.

Apollo, promising that he can tell only the truth, first denounces the treacherous means by which Clytemnestra killed her husband Agamemnon, “a great man” (636). He then argues that a child is biologically related only to their father, who provides the seed necessary for giving life, while the mother’s womb provides only a receptacle for the seed to grow. He proves this by citing the case of Athena, who was born without a mother from the head of her father Zeus.