Who is known for the creation of the twelve-tone system of atonal music?

The twelve-tone system of atonal music was developed by Arnold Schoenberg in the early 20th century. This compositional technique is significant because it revolutionized the approach to melody and harmony, moving away from traditional tonality. Schoenberg's twelve-tone method involves using all twelve notes of the chromatic scale in a specific sequence, or 'row,' which serves as the basis for a composition. This innovative approach allows for greater freedom in musical expression and creates works that do not adhere to the tonal hierarchies typical of earlier music.

Schoenberg's influence on the course of modern music is profound, as his ideas paved the way for many composers who followed. The twelve-tone system marked a radical shift in compositional practices, making it a cornerstone of 20th-century music theory and practice. The other listed composers contributed significantly to music but did not create the twelve-tone system: Stravinsky was known for his neoclassical works and ballets, Debussy was a pioneer of impressionism in music, and John Cage was renowned for his avant-garde and experimental pieces.