 In January 1952 Stockhausen travelled to Paris to study with Olivier Messiaen, and by March had become familiar with composers such as Pierre Boulez, Jean Barraqué, and Michel Philippot who were working with musique concrète at Pierre Schaeffer's Club d’Essai.Beginning in November, Stockhausen was able to work in the studio, but only recording and cataloguing natural sounds, mainly of percussion instruments.In December, at last, Stockhausen was allowed to make his own piece.