Music drama in three acts. Libretto by the composer, based on Gottfried von Strassburg's 13th century version of a medieval Breton legend. Music by Richard Wagner. First performed on 10 June 1865 at the Munich Court Theatre. First performed at the Gran Teatre del Liceu on 8 November 1899.

Wagner made Tristan und Isolde into the most forceful expression of that indomitable passion which prevails over the lovers' own wills, the rules of morality and divine law, finding fulfilment only in death. The new type of music he used, with its fierce chromaticism, reached the outer limits of tonality and marked a pivotal point in Romantic opera while opening up new paths towards the music of our own times.

Tristan und Isolde is one of the most important operas ever written on account of its magnificent score and the contribution it made to the evolution of present-day music.

The action is reduced to the bare essentials, while the key aspects of the drama are related by the music.