Greek mythology? Re Leda and the Swan, Agamemnon and his wife?

[universitystudent]

I'm writing a paper, re Yeats' "Leda and the Swan". I just need some mythology background, and am having a hard time getting a straight story. I know that Leda winds up having 4 babies from that day when Zeus comes as a swan and rapes her. The important ones for me are Helen and Clytemnestra. Helen is abducted by the Trojans? So Agamemnon, king of Argos, goes to help his bro (Helen's husband). Sacrifices his daughter to get a favourable wind. So, trojan war is 10 yrs, he comes back to Argos, where wife Clytemnestra is queen. She kills him for sacrificing their daughter. That's the version Yeats deals with. This is where i'm stuck. What happens after Agamemnon dies? Does Argos fall? Is it kind of an end for a great city and civilization? The paper asks to discuss how the rape was a turning pt in history (obviously Clytemnestra's conception). Just need to know what happens after.

[Thalia]

After Agamemnon is murdered, Queen Clytemnestra and Aegisthus rule Mycenae.

Clytamnestra's daughter Electra smuggles her young brother Orestes out of the palace. He is then hidden away in the court of the king of Phocis.

Later when Orestes is grown he returns to Mycenae, meets with Electra, and avenges his father by killing Clytemnestra and her lover. I think he also kills their little son, but their daughter Erigone manages to escape to Athens.

After the murder of his mother, Orestes is haunted by her ghost and the Erinyes -- goddesses who avenge the dead. He is eventually purified by Apollo of the crime, and returns to become king of Mycenae.

After the death of his uncle King Menelaus in Sparta, Orestes is invited to take that throne as well. He had married Hermione, the daughter of Menelaus and Helen.

The story is told in Sophocles' Oresteia trilogy.

For lots of information on Leda, try http://www.theoi.com/Heroine/Leda.html
The Greeks poets were really inconsistent about the egg-story!