Summary This work is centered on the figure of Claude Debussy in the years between 1884 and 1902 - from the moment he captured the Prix de Rome to the premiere of Pell as et M lisande, the work that marked his coming of age as a professional musician and confirmed his personal style. This period bore witness to one of the most profound transformations of the composer's musical style and the ascent of his career to dizzying heights. Debussy's creative achievements are placed in the context of his professional development as well as his interactions with various musical institutions such as the Conservatoire, the Institut des Beaux-Arts (during the Prix de Rome), the Soci t Nationale de Musique, and the Op ra-Comique. Detailed and cursory analyses of a wide range of works, both canonical and little-known, provide a window on how Debussy's style was positioned with respect to other composers of his time who hailed from both the establishment and the avant-garde (Thomas, Massenet, Chabrier, Franck, D'Indy, Grieg, Wagner). This study allows for a more nuanced understanding of our received knowledge and a refreshed historical perspective that begs us to reconsider various aspects of the artist's life. These include the clich that Debussy was widely misunderstood in his youth, and a common failure to acknowledge the influence of Mussorgsky's fellow Russians, like Balakirev and Rimsky-Korsakov. TABLE OF CONTENTS Remerciements Abr viations et conventions Introduction Chapitre 1 Autour de la Cantate L'Enfant prodigue (1884) Chapitre 2 Le s jour Rome, les ann es de boh me et l' poque des grandes mutations stylistiques (1885-1893) Chapitre 3 Le Balcon (1888) et La Mort des amants (1887) Chapitre 4 Les changes de Debussy avec Chausson et d'Indy la SNM (1888-1894) Chapitre 5 Le Quatuor cordes n. 1 Op. 10 (1893) Chapitre 6 L'Op ra-Comique et la jeune cr ation musicale d'avant-garde (1880-1902) Chapitre 7 Pell as et M lisande (1895 et 1902) Conclusion Post rit et pouvoir expressif de l' criture stratifi e debussyste (1903-1917) Bibliographie Appendices Glinka, Rousslan et Ludmilla (Ruslan i Lyudmila), Acte iv, n. 21, mes. 20-24, 39-49 791 Rimski-Korsakov, La Jeune fille de Pskov (Pskovityanka), Acte iii, sc ne 1, p. 164/2/1 (Belwin-Mills, 1982) Borodine, La Mer (More), mes. 53-60 Index