Elektra, a tragedy in one act by H. von Hofmannsthal, published in 1904. Hofmannsthal described it as ‘frei nach Sophokles’. Elektra, one of Agamemnon's two daughters, lives only for revenge on her mother the murderess, and Aegisth the murderer, which she believes will be carried out by Orest. Two strangers arrive and announce the death of Orest. Elektra now feels bound to do the deed herself, but her more cautious sister Chrysothemis holds back. The younger stranger reveals himself to be Orest and murders first Clytemnestra and then Aegisth.

The Greek play depends upon the dilemma of Orestes, who is bound to avenge his father, yet in doing so must commit matricide, one of the worst of crimes. Hofmannsthal's play conforms to Greek tragedy in the undivided long single act, but dispenses with a chorus. Written in blank verse, it invokes all the resources of modern psychology in portraying the transformation in Elektra, whose hatred has become obsessional to the point of madness.

In 1906 R. Strauss decided to use it as the libretto for an opera. In this form, which uses the original text, except for a few minor cuts, Elektra was first performed on 25 January 1909. Strauss's choice of Hofmannsthal's work marks the beginning of the long collaboration between the two men.