The first recorded use of the spouse impromptu in this sense occurred in 1817, in the Allgemeine musikalische Zeitung, an idea of the publisher to describe a piano piece by Voříšek.

It didn't take long before the first generation of Romantic composers took up the idea:

• Jan Václav Voříšek was the first one to compose impromptus, in 1822.
• Franz Schubert published two sets of four Impromptus for piano op. 90 and 142 (1827). After his death 3 more unnamed piano compositions (Klavierstücke) were sometimes named Impromptus.
• Frédéric Chopin composed 4 Impromptus, including the famous Fantaisie-Impromptu.
• Robert Schumann wrote some Impromptus, published as Op. 5.
• Franz Liszt composed an Impromptu in F sharp (sometimes called Nocturne) and a piano piece named Valse-Impromptu.
• Jean Sibelius composed six impromptus for piano op. 5 (1893)

The impromptu genre remained popular all throughout the 19th century.

In the 20th century there are fewer examples of composers naming their compositions "Impromptu", e.g.:

• Gabriel Fauré composing six Impromptus between 1881 and 1913.
• Maurice Journeau composing six Impromptus between 1971 and 1974.
• Donald Martino composing Fantasies and Impromptu in 1980.
• One of Queen's compositions, performed at Wembley Stadium in 1986 is named Impromptu.

References

• New Grove Dictionary of Music and Musicians

Notes