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 and Iseult by Gottfried von Strassburg. It was composed between 1857 and 1859 and premiered at the Königliches Hoftheater und Nationaltheater in Munich on 10 June 1865 with Hans von Bülow conducting. Wagner referred to the work not as an opera, but called it "" (literally a drama, a plot, or an action). Wagner's composition of Tristan und Isolde was inspired by the philosophy of Arthur Schopenhauer (particularly The World as Will and Representation), as well as by Wagner's affair with Mathilde Wesendonck. Widely acknowledged as a pinnacle of the operatic repertoire, Tristan was notable for Wagner's unprecedented use of chromaticism, tonal ambiguity, orchestral colour, and harmonic suspension. The opera was enormously influential among Western classical composers and provided direct inspiration to composers such as Gustav Mahler, Richard Strauss, Alban Berg, Arnold Schoenberg, and Benjamin Britten. Other composers like Claude Debussy, Maurice Ravel, and Igor Stravinsky formulated their styles in contrast to Wagner's musical legacy. Many see Tristan as a milestone on the move away from common practice harmony and tonality and consider that it lays the groundwork for the direction of classical music in the 20th century. Both Wagner's libretto style and music were also profoundly influential on the symbolist poets of the late 19th century and early 20th century. Composition history Wagner was forced to abandon his position as conductor of the Dresden Opera in 1849, as there was a warrant posted for his arrest for his participation in the unsuccessful May Revolution. He left his wife, Minna, in Dresden, and fled to Zürich. There, in 1852, he met the wealthy silk trader Otto Wesendonck. Wesendonck became a supporter of Wagner and bankrolled the composer for several years. Wesendonck's wife, Mathilde, became enamoured of the composer. Though Wagner was working on his epic Der Ring des Nibelungen, he found himself intrigued by the legend of Tristan and Isolde. The re-discovery of medieval Germanic poetry, including Gottfried von Strassburg's version of , the Nibelungenlied and Wolfram von Eschenbach's Parzival, left a large impact on the German Romantic movements during the mid-19th century. The story of Tristan and Isolde is a quintessential romance of the Middle Ages and the Renaissance. Several versions of the story exist, the earliest dating