Orfeo ed Euridice (French version: Orphée et Eurydice; English: Orpheus and Eurydice) is an opera composed by Christoph Willibald Gluck based on the myth of Orpheus, set to a libretto by Ranieri de' Calzabigi. It belongs to the genre of the azione teatrale, meaning an opera on a mythological subject with choruses and dancing. The piece was first performed in Vienna on 5 October 1762. Orfeo ed Euridice is the first of Gluck's "reform" operas, in which he attempted to replace the abstruse plots and overly complex music of opera seria with a "noble simplicity" in both the music and the drama.