Nocturne in C sharp minor, B.49, "Lento con gran espressione"

The Lento con gran espressione (or Nocturne No. 20 in C♯ minor, Op. posthumous, or Reminiscence), P 1, No. 16, KK IVa/16, WN 37, is a solo piano piece composed by Frédéric Chopin in 1830. It was published posthumously in 1875.