Fantaisie-Impromptu

Frédéric Chopin's 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 It was composed in 1834 and published posthumously in 1855 although he had instructed that none of his unpublished manuscripts should be published. Despite negative comments, the Fantaisie-Impromptu is one of Chopin's most frequently performed and popular compositions.

The Fantaisie-Impromptu was written in 1834, as were the Four Mazurkas (Op. 17), and the Grande valse brillante in E-flat major (Op. 18), but, unlike these other works, Chopin never published the Fantaisie-Impromptu. Instead, Julian Fontana published it posthumously, along with other waltzes Opp. 69 and 70. It is unknown why Chopin did not publish the Fantaisie-Impromptu. James Huneker, trying to guess why Chopin did not publish the Fantaisie-Impromptu, calls parts of it "mawkish" and "without nobility". Ernst Oster writes that a technical exploration would show why Chopin did not publish the work, and that exploration shows that the Fantaisie-Impromptu and Beethoven's Moonlight Sonata ("Quasi una fantasia") are related.

The mystery may have been solved in 1960 when pianist Arthur Rubinstein acquired the "Album of the Baroness d'Este" which had been sold at auction in Paris. The album contained a manuscript of the Fantaisie-Impromptu in Chopin's own hand, dated 1835, stating on the title page in French "Composed for the Baroness d'Este by Frédéric Chopin". The facts of its authenticity having been "guaranteed by the French authorities" and that it shows "a delicate care for detail" and "many improvements in harmony and style" in comparison to the previously published version, Rubinstein considered absolute proof that it is the finished work. In his preface to the "Rubinstein Edition", published by G. Schirmer, Inc. in 1962, Rubinstein surmises that the words "Composed for" in place of a dedication imply that Chopin received a paid commission for the work, so he had actually sold it to the Baroness.

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