About this work
The terms "Partita diverse," "partite diverse," "chorale partite," and "chorale variations" are fairly interchangeable and refer to a set of variations on a church chorale prelude or organ chorale. These, in turn, are terms that refer to a solo organ presentation of a Lutheran chorale melody (in whole or in part), rooted in the idea of playing the melody of a hymn before the congregation was to sing it, in order to familiarize them with the tune. Church organists of Bach's caliber often improvised on these familiar chorale themes and sometimes preserved their improvisations as sets of variations.
Bach left four sets of chorale variations that are fully accepted as his, of which this one is the largest, best integrated, and most comprehensive in the variety of variation techniques and textures that it employs. The first three sets are all relatively early works. The final set of chorale variations, the Canonic Variations on "Von Himmel hoch," was written quite late in Bach's life.
The exact timing of composition of this and the other early chorale partitas causes lively discussion among Bach scholars. The first two might have been written when he worked in Lüneberg when he was between 15 and 17 years old and had a chance to work with Georg Böhm, a composer prolific in the chorale variation genre. Others point to the fine part-writing and motivic development that developed later in Bach's career. The style is consistent with compositions written in Arnstadt and Mühlhausen, where Bach worked until 1708, when he entered the service of Duke Wilhelm Ernst of Saxe-Weimar. Some scholars point out that Bach was known to write music in the style of this partita during his Weimar years.
At any rate, this is a very inventive set of 11 variations on the theme of the chorale "Sei gegrüsset, Jesu gütig," (I Greet Thee, Merciful Jesus). The composition quotes the chorale in full as its opening statement, then presents its series of variations, using different variation techniques in each one. The other two sets of chorale variations are notable for not requiring pedals, and only five of these variations require them -- raising the possibility that Bach allowed for the music to be played by home keyboard musicians. The hymn tune itself is almost always easily heard, often in the top voice of the texture. The final section is a dazzling piece for full organ in five voices. It is possible that the individual variations in this set originated at different times and places, a supposition that is strengthened by some differences in quality among the variations.
No definitive manuscript of the work survives in Bach's hand, and it has come down in a variety of different printed editions and hand copies made by others. These sources have some differences in detail and in the order of the variations themselves.