Electra. After JDR (by RTM): The daughter of Agamemnon and Clytemnestra and sister of Iphigenia, Orestes, and Chrysothemis, Electra appears fully developed in Aeschylus' Oresteia, produced in Athens in 458 BCE. Homer does not know this Electra. Stesichorus mentioned her in his Oresteia, before 550 BCE.
     The central play in Aeschylus' trilogy, Choephori (Libation Bearers) treats the response of Agamemnon's children to his murder at the hands of Aegisthus and Clytemnestra. The play features the role of Orestes and renders his sister as his chief mortal instigator. In the Eumenides, indeed by the end of Aeschylus' text, she has vanished.
     A variant of the legend is told in Sophocles' Electra of approximately 418-410 BCE. After the murder of Agamemnon, Clytemnestra has been plagued by disturbing dreams and orders Chrysothemis to offer libations at Agamemnon's tomb. This inflames Electra, who is determined to avenge the murder. When Orestes and Pylades reach Argos they send out a false report of Orestes' death. Electra, who has been awaiting Orestes' arrival to exact revenge, now decides to kill Clytemnestra and Aegisthus herself and tries unsuccessfully to persuade Chrysothemis to join her pact. However, before she can act Orestes and Pylades enter the palace and perform the executions. Euripides' Electra, composed during the same period, follows a similar story line with slight variations, especially including Electra's marriage to a poor farmer, arranged by Aegisthus and Clytemnestra (to ensure that she would bear no son with a claim to the throne) and her equal participation with Orestes in the murder of their mother.
     The Orestes of Euripides, composed in 408 BCE, plays yet another variation on the theme. Six days after Clytemnestra's death now, Orestes has been crushed by the Erinyes, and both siblings are charged with matricide and sentenced to death by the Argives. Menelaus, returning from Troy with his wife, Helen, arrives in Argos and assumes the regency but refuses to aid his brother's offspring in their legal plight. With the support of Pylades, Orestes and Electra apprehend Helen to murder her. When she miraculously vanishes they seize her daughter Hermione as hostage and set the palace afire. Amid the confusion Apollo appears with Helen beside him, deus ex machina, explaining that Helen has been apotheosized and that Orestes is destined to be tried and acquitted at Athens, to be married to Hermione, and to become ruler of Argos; Electra is to marry Pylades.
    Interest into Electra's psychology expressed by Freud and Jung sparked keen interest in Electra at the beginning of the 20th-century. This fueled a revival of Electra's role in received mythology in many arts from opera to cinema and graphic novels to the present day. R. Strauss' Elektra (1909), an acknowledged adaptation of Sophocles' play, powerfully represents the psychology of the emotionally battered girl turning to matricidal vengeance. Eugene O'Neill masterfully brought the matricide to the American stage in Mourning Becomes Electra (1931) (click).
    
    

See also Orestes, Clytemnestra, Agamemnon, Iphigenia