The Nocturne No. 20 in C-sharp minor, Op. posth., Lento con gran espressione, P 1, No. 16, KKIVa/16, is a solo piano piece composed by Frédéric Chopin in 1830 and published in 1870. Chopin dedicated this work to his older sister Ludwika Chopin, with the statement: "To my sister Ludwika as an exercise before beginning the study of my second Concerto".[1][2] First published 21 years after the composer's death, the piece is usually referred to as Lento con gran espressione, from its tempo marking. It is sometimes also called Reminiscence.[3] The piece was played by Holocaust survivor Natalia Karp for the Nazi concentration camp commandant Amon Goeth, with Goeth being so impressed with the rendition that he spared Karp's life.