Prelude and Fugue in E minor, BWV 855

Alexander Siloti made a piano arrangement in B minor of the Prelude BWV 855a.

Where the 1998 version of the Bach-Werke-Verzeichnis (BWV2a) described BWV 855a as only a Prelude, based on its appearance in the Klavierbüchlein für Wilhelm Friedemann Bach,[2] BWV 855a may also refer to both this Prelude and a Fughetta in E minor, found in a manuscript copy made between 1750 and the early 19th century, once owned by F. Konwitschny but later lost.

Siloti also adds a repeat of the entire work, in order to allow for a change of voicing where the melody in the left hand is emphasized.

[8] In the published score, above, the chords in the left hand are arpeggiated; however, according to Siloti's daughter Kyriena (to whom the work was dedicated[8]), he would omit the arpeggiation on the first pass and restore it on the repeat in order to heighten the effect of the left-hand melody.

[8] The date of the arrangement is uncertain: it was first published by A. Gutheil of Moscow,[9] and was performed by Siloti in public for the "first time" (according to an announcement in the Manchester Guardian) in February 1912.