The Oresteia

The Oresteia is a trilogy of Greek plays, centering around an ancient Greek woman named Cassandra.

The specific play seen in Scream 2 (1997 film) is "Agamemnon", and it can be identified because Cassandra and the chorous are wondering if she should enter the palace, since she knows she will die if doing so.

The Windsor College Murders
During the Windsor College killing spree, Sidney Prescott informs Dewey that theater is going "great" and she has first starring role; they are due to open for the public in two days. The play is "Agamemnon", and she has landed the leading role as Cassandra specifically. She states she is nervous about performing due to the murders.

Her drama professor, Gus Gold, explains he understands but Sidney must do so anyway. Though, he also explains it is because there is no understudy. He explains she is a fighter, and like Cassandra, Sidney is cursed, and learned to embrace it.

During rehearsal for the play, a scene from after the fall of Troy, Ghostface, wearing a brown cloak just as the chorus is wearing, arrives and attacks Sidney during a scene of mass chaos where the chorous is running around chasing her with fake daggers. Sidney finally collapses and screams, although it is not clear if this is simply a figment of Sidney's imagination or not.

If Ghostface really did attack, it is likely that the killer was Mickey, since he was in the area at the time. Most likely Sidney did not imagine the attack, because you can see Ghostface run away.

Later in the film, Sidney uses props from the play to her advantage, using the pillars to knock down Nancy Loomis. This is foreshadowed during the original play scene when you can see falling bricks from the unstable set.

Significance
Coincidentally, The Oresteia is a trilogy that appears in the second installment of the Scream franchise, which would later become a trilogy of its own in 2000.

Another interesting note is that The Oresteia is a tragedy focusing around a single female heroine, Cassandra. The Scream trilogy is also a tragedy focusing around a single female heroine, Sidney Prescott.

The Oresteia is about Cassandra's life after she is cursed by Apollo. The Scream franchise is about Sidney's life after her mother's death, which can be considered a "curse" as it sets in motion the tragic events of the entire series.

A running theme in this play trilogy is murder and revenge. Clytemnestra kills Agamemnon for sacrificing their daughter and having an affair, and Orestes, their son, seeks revenge for his father's death and mother's affair by killing Clytemnestra, his mother. In this movie, Nancy Loomis is seeking revenge from Sidney for the death of her son, who killed Sidney's mother for having an affair with his father. The climax of this film about familial murder and revenge plays out on the set of the play about familial murder and revenge.