Arnold Franz Walter Schoenberg (September 1874 - 13 July 1951) was an Austrian composer, associated with the expressionist movement in German poetry and art, and leader of the Second Viennese School. His name would come to personify pioneering innovations in atonality that would become the most polemical feature of 20th century art music. In the 1920s, Schoenberg developed the twelve-tone technique, a widely influential compositional method of manipulating an ordered series of all twelve notes in the chromatic scale. He also coined the term developing variation, and was the first modern composer to embrace ways of developing motifs without resorting to the dominance of a centralized melodic idea. Schoenberg was also a painter, an important music theorist, and an influential teacher of composition. His superstitious nature may have triggered his death. In 1950, on his 76th birthday, an astrologer wrote Schoenberg a note warning him that the year was a critical one: 7 + 6 = 13. This stunned and depressed the composer, for up to that point he had only been wary of multiples of 13 and never considered adding the digits of his age. He died on July 13, 1951, shortly before midnight.