His reputation as a composer continued to grow and in 1959, he was nominated as an "Officier" of the "Légion d'honneur". In 1966 he was officially appointed professor of composition at the Paris Conservatoire, although he had in effect been teaching composition for years. Further honours included election to the Institut de France in 1967 and the Académie des beaux-arts in 1968, the Erasmus Prize in 1971, the award of the Royal Philharmonic Society Gold Medal and the Ernst von Siemens Music Prize in 1975, the Sonning Award (Denmark's highest musical honour) in 1977, the Wolf Prize in Arts in 1982, and the presentation of the "Croix de Commander" of the Belgian Order of the Crown in 1980.