About this work
Ein feste Burg (A Mighty Fortress) can best be described as a chorale fantasia. This type of piece differs from other chorale preludes by its free treatment of the tune, often obscuring it with ornaments and improvisatory gestures.
Ein feste Burg, based on Luther's hymn, is usually played on Reformation Sunday. The heading indicates it was written for a 3-manual organ, but the original registration only specifies a 16' Fagotto in the swell and a Sesquialtera in the great. The style of this piece recalls the North German school of Baroque composers, with dialogue exchanged between voices and various changes in dynamics and texture. The tunes alternate between both hands and the feet, and the strongest quotation of the melody sounds on the pedal (usually a Trumpet) in the middle of the piece.
For many years, it was believed that Ein feste Burg ist unser Gott was one of the miscellaneous chorales of Johann Sebastian Bach that was transmitted by Bach's students. It is known in four extant manuscripts, and at one time was known in two others; thankfully the latter of these lost items was microfilmed before the original disappeared. The main manuscript version known to Bach's editors in the nineteenth century (D B Mus. ms. Bach P 802) was compiled before 1740 by Johann Gottfried Walther, Johann Ludwig Krebs and the latter's two brothers. There it appears as an unattributed work among a number of pieces known to have been written by Johann Sebastian Bach, and so it was included without comment in the 1893 collection of Bach's collected organ works issued in 1893 as BWV 720. The piece also appears in a manuscript collection(D B Mus. ms. Bach P 806) compiled by F. A. Grasnick around 1800, seemingly with no attribution. But recent examination of the manuscript revealed that in this case the author's name was placed at the end - Johann Michael Bach, Johann Sebastian's uncle, who died in 1694. Checking against the little known microfilm of the lost source, which was copied by Johann Gottfried Walther, it was confirmed that Walther did indeed indicate that Johann Michael Bach was the composer of this little setting of Ein feste Burg.