Tristan und Isolde (Tristan and Isolde), WWV 90, is an opera in three acts by Richard Wagner to a German libretto by the composer, based largely on the 12th-century romance Tristan by Gottfried von Strassburg. It was composed between 1857 and 1859 and premiered at the Königliches Hof- und Nationaltheater in Munich on June 10, 1865 with Hans von Bülow conducting. Wagner referred to the work not as an opera, but called it "eine Handlung" (literally a drama, a plot or an action). The Prelude and Liebestod is a concert version of the overture and Isolde's act 3 aria, "Mild und leise". The arrangement was by Wagner himself, and it was first performed in 1862, several years before the premiere of the complete opera in 1865. The Liebestod can be performed either in a purely orchestral version, or with a soprano singing Isolde's vision of Tristan resurrected.