Penthesilea is a one-act opera by Othmar Schoeck, to a German-language libretto by the composer, after the work of the same name by Heinrich von Kleist.
[1] Robin Holloway has noted the similarity of theme to Richard Strauss' Elektra, as well as Schoeck's use of two pianos in the instrumentation.
[2] The story is about the tragic love of Penthesilea, queen of the Amazons, and Achilles.
However, she finally does learn the truth, that in fact he defeated her in battle, and her love for him becomes hatred.
In her anger, she takes up the challenge, and in the duel, she savagely kills him.