Fantaisie-Impromptu Nr. 4 cis-moll, Op.66

Frédéric Chopins Fantaisie-Impromptu in C-sharp minor, Op. posth. 66, is a solo piano composition. It was composed in 1834 and published posthumously in 1855 although he had instructed that none of his unpublished manuscripts should be published.[1] Despite negative comments, the Fantaisie-Impromptu is one of Chopins most frequently performed and popular compositions.