Arnold Schoenberg was one of the most influential composers of the 20th century, but perhaps also one of the least listened to. Strikingly, Schoenberg was self-educated, even though his music is imbedded in complex music theory. It was Schoenberg who definitely departed from tonality and he developed the twelve tone technique. In this composition style, one has to use every twelve tones of the scale, before one can be repeated. The struggle to adhere to this dogma is clearly audible: his music is tense, hectic and particularly acute - and therefore at times not that accesible to occasional listeners.
Nevertheless, his music and his liberation of tonality had an enormous impact on all composers that came after him. Together with the music of his students Alban Berg and Anton Webern, his style is often referred to as the Second Viennese School, parallel to the First Viennese School of Mozart, Haydn and Beethoven, who, in a similar vein, changed the history of music for good.
His most performed works are his string sextet Verklärte Nacht, his five Orchestra pieces op. 16, and his opera Moses und Aron. The development of Schoenberg's music can be heard in his Five String Quartets in particular.