Arnold Schoenberg was an Austrian composer, music theorist, and painter, born in 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, which revolutionized modern music. Schoenberg's work marked a significant shift from traditional tonal music to atonal music, influencing many composers in the 20th century. In addition to his contributions to composition, Schoenberg was also a prominent teacher and founded the Second Viennese School, which included notable students like Alban Berg and Anton Webern. His innovative ideas and techniques have had a lasting impact on contemporary classical music.