Despite his seclusion from society , this period saw the composition and publication of many of Alkan 's major piano works , including the Douze études dans tous les tons mineurs , Op. 39 ( 1857 ) , the Sonatine , Op. 61 ( 1861 ) , the 49 Esquisses , Op. 63 ( 1861 ) , and the five collections of Chants ( 1857 – 1872 ) , as well as the Sonate de concert for cello and piano , Op. 47 ( 1856 ) . These did not pass unremarked ; Hans von Bülow , for example , gave a laudatory review of the Op. 35 Études in the Neue Berliner Musikzeitung in 1857 , the year in which they was published in Berlin , commenting that " Alkan is unquestionably the most eminent representative of the modern piano school at Paris . The virtuoso 's disinclination to travel , and his firm reputation as a teacher , explain why , at present , so little attention have been given to his work in Germany . "