Charles-Valentin Alkan was a French composer and one of the greatest virtuoso pianists of his day. He entered the Paris Conservatoire at the age of six, earning many awards, and as an adult became a famous virtuoso and teacher. Although early in his life he was socially active and good friends with prominent musicians and artists including Eugène Delacroix, Franz Liszt and Frédéric Chopin, he gradually withdrew from the concert platform after 1848, and he lived a reclusive life in Paris until his death. Like Chopin, Alkan wrote almost exclusively for the keyboard, although in Alkan's case this included the organ and the pédalier (a piano with a pedal board), of which he was a noted exponent. Some of his music requires a dazzling virtuosity, calling for extreme velocity, enormous leaps at speed, long stretches of fast repeated notes, and the maintenance of widely-spaced contrapuntal lines. His music has been reviewed as "ferociously" and even "impossibly" difficult to play.