A slow and painstaking worker, Ravel composed fewer pieces than many of his contemporaries. Among his works to enter the repertoire are pieces for piano, chamber music, two piano concertos, ballet music, two operas and eight song cycles; he wrote no symphonies or church music. Many of his works exist in two versions: first, a piano score and later an orchestration. Some of his piano music, such as "Gaspard de la nuit" (1908), is exceptionally difficult to play, and his complex orchestral works such as "Daphnis et Chloé" (1912) require skilful balance in performance.