Contemporary classical music is classical music composed close to the present day. At the beginning of the 21st century, it commonly referred to the post-1945 modern forms of post-tonal music after the death of Anton Webern, and included serial music, electronic music, experimental music, and minimalist music. Newer forms of music include spectral music, and post-minimalism. History Background At the beginning of the twentieth century, composers of classical music were experimenting with an increasingly dissonant pitch language, which sometimes yielded atonal pieces. Following World War I, as a backlash against what they saw as the increasingly exaggerated gestures and formlessness of late Romanticism, certain composers adopted a neoclassic style, which sought to recapture the balanced forms and clearly perceptible thematic processes of earlier styles (see also New Objectivity and Social Realism). After World War II, modernist composers sought to achieve greater levels of control in their composition process (e.g., through the use of the twelve-tone technique and later total serialism). At the same time, conversely, composers also experimented with means of abdicating control, exploring indeterminacy or aleatoric processes in smaller or larger degrees. Technological advances led to the birth of electronic music. Experimentation with tape loops and repetitive textures contributed to the advent of minimalism. Still other composers started exploring the theatrical potential of the musical performance (performance art, mixed media, fluxus). New works of contemporary classical music continue to be created. Each year, the Boston Conservatory at Berklee presents 700 performances. New works from contemporary classical music program students comprise roughly 150 of these performances. 1945–75 To some extent, European and the US traditions diverged after World War II. Among the most influential composers in Europe were Pierre Boulez, Luigi Nono, and Karlheinz Stockhausen. The first and last were both pupils of Olivier Messiaen. An important aesthetic philosophy as well as a group of compositional techniques at this time was serialism (also called "through-ordered music", "'total' music" or "total tone ordering"), which took as its starting point the compositions of Arnold Schoenberg and Anton Webern (but was opposed to traditional twelve-tone music), and was also closely related to Le Corbusier's idea of the modulor. However, some more traditionally based composers such as Dmitri Shostakovich and Benjamin Britten maintained a tonal style of composition despite the prominent serialist movement. In America, composers like Milton Babbitt, John Cage, Elliott Carter, Henry Cowell, Philip Glass, Steve Reich, George Rochberg, and Roger Sessions,