why does Agamemnon sacrifice his daudgter?

The Chorus continues its exposition, now directing it toward the queen. They ask about the sacrifices she has ordered in the city. The Chorus is not aware the signal has arrived and the war is over. The portent of the hare-a pregnant hare from whom the fetus was torn out-is discussed. It occurred just before the war, when a seer read it and forecasted disaster for Argos. The Chorus then relates the historical event, the playing out of the portent, in which Agamemnon chose to sacrifice his young daughter Iphigenia for the sake of the war effort.