ENThe chapter by Rūta Stanevičiūtė examines Hába’s creative impulses, which laid the foundations for the modernization of music beyond the great centers of new music in Europe by exploring the beginnings of microtonal music in Lithuania. By the mid-1930s with composers’ massive emigration from Germany and Austria, the position of the Prague school of microtonal music as a milieu of the musical avant-garde in the international modern music scene and especially in the environment of the ISCM became stronger. At the time, Alois Hába was especially concerned with the broader representation of his school, and he simultaneously managed to promote his own musical doctrine via his pupils’ activities in Central and Eastern Europe. In this chapter the author discusses the effort of Lithuanian composer Jeronimas Kačinskas (1907–2005), a pupil of Hába and an outstanding follower of the Czech composer’s microtonal school, to institutionalize microtonality. During his study years, Kačinskas became one of the most prominent adherents of the Hába “school” and continued to consistently deploy the quarter-tone system in his works throughout the 1930s. Having returned to Lithuania in 1931, he seized the opportunity to establish a class on quarter-tone music at the Klaipėda Music School and promulgated ideas of microtonal music in his writings.Kačinskas and some fellow musicians founded the music magazine Muzikos barai (Domains of Music) in 1932, which often featured articles by the proponents of the quarter-tone and avant-garde music of the time, such as Hába himself, Karel Ančerl, Karel Reiner, and Mirko Očadlík. To effectuate the dissemination of quarter-tone music in Lithuania he co-founded, in 1932, the Society of Progressive Musicians with a group of like-minded composers, which organised the first Lithuanian tour of the famous Czech Nonet the same year. Along with other contemporary pieces, these concerts featured the world premiere of Kačinskas’s Nonet (1931–2/1936) written especially for this ensemble, which was later included in the program of the 1938 ISCM Festival in London. Hába regarded Kačinskas’s Nonet among the most remarkable accomplishments in the modern music of the 1930s and several times included this work in concerts that represented his school of composition. However, the abrupt change in political and artistic climate in the middle of the twentieth century precluded the realization of Kačinskas’s ambitions to the extent he would have imagined. After many years in emigration, Kačinskas regrettably admitted that Hába’s system failed to realize its full potential, his microtonal theory did not receive wider acceptance and was supplanted, as he said, by musique concrete. After Kačinskas’s emigration to the United States in the aftermath of World War II, for many decades the Nonet has been the only known example of his microtonal music. Relying on the newly discovered autographs of his microtonal works (for example, Concerto for trumpet and symphony orchestra, 1930–1; Trio No. 1 for trumpet, viola and piano, 1933) and scarcely researched archival documents, this chapter argues the originality of Kačinskas’s microtonal compositions and examines their international spread in the context of the Hába school.