Frédéric Chopin's Impromptu No. 2 in F-sharp major, Op. 36 was composed in 1839 and published in the following year.
Music
The Impromptu begins with a nocturne-esque chord. The piece is in the less commonly used key of F-sharp major, which is used in very few major compositions in the Romantic era, such as Ludwig van Beethoven's A Thérèse sonata and Chopin's famous Barcarolle.
References
Impromptu No. 2 (Chopin) Wikipedia(Text) CC BY-SA