Franz Schubert - Impromptus

The term Impromptu, fashionable for a short time in the first half of the 18th century, designates a free-form composition, for the most part highly organized, but retaining something of the sense of being the result of a sudden inspiration.
Schubert’s Impromptus are among the most famous examples of the genre, but the title Impromptu was not assigned to these pieces by the composer himself but by the Viennese publisher Haslinger.
The two sets D. 899 and D. 935 were both written in 1827. Three other unnamed piano compositions, D. 946, written a few months before the composer´s death in 1828, are alternatively referred to as Impromptus or Klavierstücke.