 Alkan earned many awards at the Conservatoire de Paris , which he entered before he was six . His career in the salons and concert halls of Paris was marked by his occasional long <unk> from public performance , for personal reasons . Although he had a wide circle of friends and acquaintances in the Parisian artistic world , including Eugène <unk> and George Sand , from 1848 he began to adopt a reclusive life style , while continuing with his compositions – virtually all of which are for the keyboard . During this period he published , among other works , his collections of large @-@ scale studies in all the major keys ( Op. 35 ) and all the minor keys ( Op. 39 ) . The latter includes his Symphony for Solo Piano ( Op. 39 , nos . 4 – 7 ) and Concerto for Solo Piano ( Op. 39 , nos . 8 – 10 ) , which are often considered among his masterpieces and are of great musical and technical complexity . Alkan emerged from self @-@ imposed retirement in the 1870s to give a series of recitals that were attended by a new generation of French musicians . 
