Alban Berg, Anton Webern & Arnold Schoenberg were the principle members of the Second Viennese School. Their music was initially characterized by post-romantic expanded tonality and later, following Schoenberg’s own evolution, a totally-chromatic expressionism without firm tonal centre (often referred to as atonality) and later still Schoenberg’s serial twelve-note technique.
Membership of the ‘School’ is not generally extended to Schoenberg’s many pupils in the USA from 1933, such as John Cage, Leon Kirchner and Gerald Strang, nor to many other composers who, at a greater remove, wrote compositions evocative of the ‘Second Viennese’ style, such as the celebrated Canadian pianist Glenn Gould. By extension, however, certain pupils of Schoenberg’s pupils (such as Berg’s pupil Hans Erich Apostel and Webern’s pupils René Leibowitz, Leopold Spinner and Ludwig Zenk) are usually included in the roll-call.
The existence of a ‘First Viennese School‘ is debatable. The term is often assumed to connote the great Vienna-based masters of the Classical style working in the late 18th and early 19th century, particularly Wolfgang Amadeus Mozart, Joseph Haydn, Ludwig van Beethoven and Franz Schubert.