Greek-born Iannis Xenakis (1922-2001), who became a French citizen in 1965, is considered one of the most exact of the modernist composers who created a furore after World War II. He developed an interest in Greek and Byzantine church music at an early age, yet between 1940 and 1947 he studied to become an engineer and architect. During World War II, he was part of the resistance against the German occupation and was wounded in the face, arrested and sentenced to death in 1945. To the accusation that his music was cold, Xenakis once said that all his works incorporated his experiences of the Greek resistance. 

In 1947, he emigrated to France, where he worked as an assistant to the famous architect Le Corbusier; among other things, he was involved in the design for the Philips Pavilion at the 1958 World's Fair in Brussels. In the early 1950s, he simultaneously studied at the Paris Conservatoire, with composers such as Arthur Honegger, Darius Milhaud and Olivier Messiaen. In his composing, he moved rapidly from serialism to aleatoricism and compositional methods that leaned on statistical analysis of musical material. Xenakis himself often spoke of his music in terms of "stochasticism": this music is not determined by randomness, but allows one of the most probable to emerge from the many possibilities. The premiere of Metastasis at the Donaueschinger Musiktage in 1955 marked his breakthrough to the international top of new music. At the Paris École pratique des hautes études, he founded and led the interdisciplinary working group Équipe de Mathématique et d'Automatique Musicales. From 1972, he also taught at the Sorbonne. Together with Pierre Boulez, he founded IRCAM in Paris, but later withdrew from the institute.