Chopin-Nocturne No. 21 in C minor, Op. posth. – is a musical work for solo piano composed in 1847-1848. It was the last of Chopin’s nocturnes to be published, and was done so posthumously in 1938. It is famous for its striking simplicity and folk-like melody. Among the 21 nocturnes known to have been written by Chopin, this is one of the three that end in a minor key