Who is Atreus, and why is he important?

Atreus, who is Agamemnon's father, does not physically appear in any of the three plays, but he is referred to several times. His actions, which include the killing of his brother Thyestes' children and the tricking of Thyestes into eating their flesh, are in the minds of both the human characters and the immortals. His deeds are the source of the fatal, so-called "curse" that has followed Atreus' descendants throughout the years. Atreus can therefore be seen as a symbolic embodiment of the dangerous, corruptive, potentially evil power of ambition - he wanted absolute control over his kingdom and so did whatever it took to put Thyestes out of the picture. The mythic stories of Agamemnon, Orestes and Electra, as well as of Agamemnon's sacrificed daughter, Iphigenia, are often referred to under the umbrella heading of "The House of Atreus".