he had become acquainted with in 1889 at the Paris 1889 World's Fair, can be observed for the first time. In this context, the work of Béla Bartók, who had already explored most of the fundamental characteristics of his new style by means of a systematic study of Balkan folklore in 1908, is to be regarded as exemplary. In the course of this development, Bartók arrived at the treatment of the "piano as a percussion instrument" with his Allegro barbaro (1911), which subsequently had a decisive influence on composers' treatment of this instrument. The rhythmic complexities peculiar to Slavic folklore were also appropriated by Igor Stravinsky in his early ballet compositions written for Sergei Diaghilev's Ballets Russes. Significantly, Stravinsky uses a given "barbaric-pagan" stage plot for his most revolutionary experiment in this respect (The Rite of Spring 1913). It was also Stravinsky who, in the further course of the 1910s, developed his compositional style in a direction that became exemplary for Neoclassicism. In France, various young composers appeared on the scene who devoted themselves to a similar emphatically anti-romantic aesthetic. The Groupe des Six was formed around Erik Satie, whose leading theoretician was Jean Cocteau. In Germany, Paul Hindemith was the most prominent representative of this movement. The proposal to use the canon of musical forms, such as the Baroque, to renew the musical language had already been put forward by Ferruccio Busoni in his Draft of a New Aesthetic of Musical Art. In the spring of 1920, Busoni formulated this idea again in an essay entitled Young Classicism. Furthermore, the radical experiments devoted to the possibilities of microtonal music are exceptional. These include Alois Hába, who, encouraged by Busoni, found his preconditions in Bohemian-Moravian musicianship, and on the other hand Ivan Wyschnegradsky, whose microtonality is to be understood as a consistent further development of the sound-centre technique of Alexander Scriabin. In the wake of the Italian Futurism around Filippo Tommaso Marinetti and Francesco Balilla Pratella, which was based in the visual arts, Luigi Russolo in his manifesto The Art of Noises (1913, 1916) designed a style called Bruitism, which made use of newly constructed sound generators, the so-called Intonarumori. The spectrum of musical expression is extended by another interesting experiment that also enters the realm of the musical application of sounds, namely the tone cluster by Henry Cowell. Some of the early piano pieces by Leo Ornstein and George