There is a particular scene in "Agamemnon" that I always want to point to in order to show students the genius of Aeschylus as a tragic playwright. To really appreciate any of these ancient plays you really have to have an understanding the peculiar structure of the classic Greek drama. The better understanding you have of this structure, as well as the key elements of tragedy as delineated by Aristotle in his "Poetica," the more you can appreciate any of these plays, but "Agamemnon" in particular.
The play is the first drama of the Orestia trilogy, the only extant trilogy to survive from that period; of course, since Aeschylus was the only one of the three great tragic poets whose trilogies told basically a story in three-parts. Sophocles and Euripides would tell three different but thematically related stories in their own trilogies (the Theban trilogy of Sophocles is an artificial construct). In "Agamemnon" it has been ten years since he sailed away to Troy, having sacrificed his daughter Iphigenia in order to get fair winds (the tale is best told by Euripides in "Iphigenia at Aulis"). For ten years Agamemnon's wife Clytemnestra, the half-sister of Helen, has been waiting for his return so she can kill him. In the interim she has taken Agamemnon's cousin Aegithus as a lover.
This brings into play the curse on the house of Atreus, which actually goes back to the horrid crime of Tantalus and the sins of Niobe as well. Atreus was the father of Agamemnon and Menelaus, who a generation earlier had contended with his own brother Thyestes for the throne of Argos. Thyestes seduced his brother's wife and was driven out of Argos by Atreus, who then became king. Thyestes eventually returned to ask forgiveness, but Atreus, recalling the crime of Tantalus, got his revenge by killing the two sons of Thyestes and feeding them to their father at a banquet. That was when Thyestes cursed Atreus and all of his descendants and fled Argos with his remaining son, the infant Aegithus.
This becomes important because Aeschylus has two people in the palace at Argos, each of whom has a legitimate reason to take the life of Agamemnon. But in this version Aeschylus lays the crime at Clytemnestra's feet. When Agamemnon returns with his concubine Cassandra, daughter of Troy's King Priam, the insane prophetess symbolizes all sorts of reasons for Cassandra to renew her desire for vengeance. However, it is also important that Agamemnon reaffirm his guilt, and this he does by his act of hubris, walking on the scarlet carpet.
Now, one of the key conventions of Greek tragedy was that acts of violence happened off stage, in the skene, which in "Agamemnon" serves as the place at Argos. Consequently, the Athenian audience not only knows that Agamemnon is going to be murdered, they know that once he goes into the "palace" he is not coming out alive and at some point a tableau of his murder will be wheeled out of the skene. However, despite this absolute knowledge Aeschylus manages to surprise his audience with the murder. This is because of the formal structure of a Greek tragedy.
Basically the tragedy alternates between dramatic episodes, in which actors (up to two for Aeschylus, three for Sophocles and Euripides) interact with each other and/or the chorus, and choral odes called stasimons. These odes are divided into match pairs of strophes and antistrophes, reflecting the audience moving across the stage right to left and left to right respectively.
After Agamemnon goes into the palace and the chorus does an ode, the next episode has Clytemnestra coaxing the doomed Cassandra into the palace as well. With both of the intended victims inside, the chorus begins the next ode. Once the first strophe is finished the corresponding antistrophe is required, but it is at that point, while the audience is anticipating the formal completion of the first pair, that Agamemnon's cry is heard from within the palace. The antistrophe is the disjointed cries of the individual members of the chorus, in contrast to the choral unity of the strophe.
This is how Aeschylus surprises his audience with the murder of Agamemnon, but using the psychology of the play's structure to his advantage. Because we do not have any examples of tragedy that predate Aeschylus, it may well be more difficult to really appreciate his innovation as a playwright. But while the Orestia as a whole is clearly his greatest accomplishment, it is perhaps this one scene that best illustrates his genius. While the fatal confrontation between Clytemnestra and Orestes in "Choeophori" has the most pathos of any of his scenes, there is nothing in either it or "Eumenides" that is as brilliantly conceived and executed as the murder of Agamemnon.
