Arnold Schönberg was an Austrian composer, music theorist, and painter, born on September 13, 1874. He is best known for developing the twelve-tone technique, a method of composition that uses all twelve notes of the chromatic scale in a specific order. This innovation marked a significant shift in the world of classical music, moving away from traditional tonal structures. In addition to his contributions to composition, Schönberg was a key figure in the Second Viennese School, which included other notable composers like Alban Berg and Anton Webern. He also wrote influential essays on music theory and aesthetics, shaping modern music's direction in the 20th century.