This dissertation investigates the relationship between György Ligeti’s soundmass works and the musical past. After his emigration in 1956, Ligeti (1923-2006) gained renown for his sound-mass style, exemplified in works such as Apparitions (1958- 59), Atmosphères (1961), Requiem (1963-65) and Lontano (1967). These works minimize the perceptual salience of melody, rhythm and harmony, instead foregrounding orchestral clusters and thus suggesting that timbre is the central compositional issue. Despite his immersion in the creative atmosphere of the Darmstadt circle, Ligeti’s soundmass works diverged from the serial, pointillist style that preoccupied the European avant-garde at the time. However, I argue that Ligeti’s distance from the Darmstadt avant-garde is only apparent. In fact, this milieu served as his primary socio-cultural reference point after his emigration. The concept of “historical memory,” following from the work of French sociologist Maurice Halbwachs (1877-1945), suggests that Ligeti’s understanding of the musical past was deeply shaped by the collective interpretations in circulation amongst the Darmstadt avant-garde circle. Analysis of Ligeti’s sketches, writings and scores shows that he recollected historical influences that were important in the discourses of his milieu and redeployed them in his sound-mass works. For example, Ligeti’s Apparitions shows traces of the analyses of Debussy’s Jeux that were produced by Herbert Eimert and Karlheinz Stockhausen. Atmosphères, though it is an acoustic work, reflects the collective representation of electronic music that had developed at the Westdeutscher Rundfunk studio in Cologne. The Darmstadt composers’ sustained interest in the concept of Klangfarbenmelodie, as practiced by both Schoenberg and Webern, informs Ligeti’s use of timbre in Lontano and the Cello Concerto. Finally, Ligeti capitalizes upon the popularity of Webern around Darmstadt, using Webern’s music as an opportunity to recast Bartók’s achievements to his new Western European colleagues in the Requiem. Ligeti’s renegotiation of the musical past, within the discourses of his Darmstadt avantgarde milieu, was crucial for his composition of the sound-mass works. / text