Bach for his pupils since their 'standard of counterpoint and general musicianship' does not fit the period in question, nor does the scarcity of copies suggest they were much used, even as part of a bigger compendium. It has not yet been possible to date the compositions, but Williams writes: 'Though frequently charming and melodious, they could hardly have been written by J. As Williams explains, whoever the composer was, the works show an ability to compose in diverse ways-the toccata, the Italian concerto, the galant style, the fughetta and the durezze style with slow suspensions, favoured by Girolamo Frescobaldi. While originally attributed to Bach, scientific examination of the extant manuscripts by Alfred Dürr in 1987 and subsequent stylistic analysis of the score by Peter Williams have suggested that the eight preludes and fugues might have been composed by one of his pupils, Johann Ludwig Krebs.

History and attribution Mid-eighteenth century manuscript copy of Prelude, BWV 555 in the durezza style of Girolamo Frescobaldi

They are now believed to have been composed by one of Bach's pupils, possibly Johann Tobias Krebs or his son Johann Ludwig Krebs, or by the Bohemian composer Johann Caspar Ferdinand Fischer.

The Eight Short Preludes and Fugues (also Eight Little Preludes and Fugues), BWV 553–560, are a collection of works for keyboard and pedal formerly attributed to Johann Sebastian Bach. The 1741 organ of Johann Andreas Silbermann in St Thomas' Church, Strasbourg

Bach prelude and fugue in b flat minor