Anyone who is interested in some pretty gruesome tragedies ought to learn about the curse on the House of Atreus. The tale begins with Tantalus, who tries to test the gods by feeding them his own murdered son, Pelops. The gods realize the trick (well, all but one of them), and curse Tantalus to stand in a pit filled with water which retreats from his mouth whenever he tries to take a sip, and with fruit trees dangling fruit forever just out of his reach.
The curse continue with Pelops (brought back to life by the gods), who promises to let a co-conspirator sleep with his bride if he helps him win her by murdering her father. When the deed is done, Pelops decides that he'd rather not follow through with his promise, and murders his co-conspirator instead, who curses him and his line.
Pelop's sons, Atreus and Thyestes, feud over rule of Argos. Thyestes sleeps with Atreus' wife, so Atreus pretends to make up with Thyestes by holding a banquet in his honor, where he serves Thyestes his own murdered children. In revenge, Thyestes rapes Atreus' daughter (and his own niece), and has a son by her, Aegisthus, who will then murder Atreus and restore Thyestes to the throne. Atreus' son, Agamemnon (he and his brother Menelaus are of Trojan war fame) kills Thyestes, and then when Agamemnon returns from the Trojan war, Thyestes' son Aegisthus takes revenge by sleeping with his wife and conspiring with her to murder Agamemnon. After Agamemnon's wife, Clytemnestra, murders Agamemnon, it falls to their son Orestes to avenge his father by murdering Aegisthus and Clytemnestra, his own mother. This is where The Orestiabegins.
I hope I got the story straight, with all its twists and turns who can keep it all in their head? In any case, the paper I wrote deals more with how Aeschylus and the ancient Greeks begin to switch their conception of justice from the tribal retribution as exemplified by the House of Atreus to civic justice, and what it meant for their understanding and formation of their own identities and consciences. Hope you enjoy!