The so-called ‘German Organ Mass’ was published towards the end
of September 1739 as the third instalment of the Clavier-Übungen
series. It was Bach’s first published work for organ. It was
also the longest and most problematic of all the printed works
that appeared during his lifetime; in many respects it was a
powerful demonstration of Bach’s skill in composition produced
against the background of a turbulent period of his life. Bach
gave the following title to the collection: Catechism and other
Hymns for the Organ. For Music Lovers and especially for
Connoisseurs of such Work, to refresh their Spirits Johann
Sebastian Bach, Royal Polish and Electoral Saxon Court Composer,
Capellmeister, and Directore Chori Musici in Leipzig. Published
by the Author. The collection consists of multiple settings of
the German Kyrie and Gloria (BWV 669-677), pairs of settings for
each of six catechism chorales (BWV 678-689) and four duets (BWV
802-805), all of which are enclosed by the prelude and fugue in
E-flat major (BWV