Arnold Schoenberg was a composer, born in Austria in 1874. He is considered one of the most influential composers of the 20th century and is known for his development of twelve-tone technique, a method of composition using all twelve notes of the chromatic scale. He was also an influential teacher, having taught many of the leading figures of the Second Viennese School. Schoenberg's works include operas, chamber music, and orchestral works.