Manuscript Mus ms P285, Rara lb 36 contains two compositions that were presumably not written by Johann Sebastian Bach. Hence their inclusion in the second supplement of the catalogue of Bach's compositions that contains the compositions where Bach's authorship is doubtfull. The first of these two compositions from Mus ms P285, Rara lb 36 is the prelude to the choral "Helft mir Gottes Güte preisen", that I already published a while ago. The second one is the prelude published here, based on the melody of "Wer nur den lieben Gott lässt walten".
The curious thing about these two compositions is that they share the same introduction and ending. The choral melodies are not the same, but they do share the first few notes. The introduction is based on the first four notes of both choral melodies, making that introduction suitable for both these two melodies. And since the ending of the composition is based on the introduction, that can be re-used as well. The part in between introduction and ending is quite different though, as the choral melodies are quite different too. But it is an efficient way of composing to just re-use suitable material.
It's impossible to know for certain which composition is the original on which the other one is based. There are some small differences in the introduction of the two compositions. The introduction to BWV Anh. II 54 is a bit more concise than the introduction to BWV Anh. II 68, making me think the first on is the original composition. But it could equally well be, that the latter is the original composition and that whoever wrote BWV Anh. II 54 just made some small improvements. We'll probably never know.
The existance of these two compositions also shows that 'originality' was not really a point the Baroque era. Suitable material was just re-used without any scruples. So, if two choral melodies are a bit alike, the material that is written for one of them, can be re-used for the other. Makes me wonder whether I can find a third melody that shares the same four starting notes as the melodies of "Helft mir Gottes Güte preisen" and "Wer nur den lieben Gott lässt walten" to re-use the same introduction a third time.
This piece is actually quite tricky to play. The manuscript says it is written for two manuals and pedals, presumably meaning the choral melody is to be played with adifferent registration as the accompaniment. In some places however, the accompaniment needs two hands, even while the choral melody is still sounding. That means I have two play with one hand across two manuals, not an easy thing to do. Another difficult spot is bars 18 and 19, where the pedals play a very awkward passage in sixteenth notes, that does not really fit in the rest of the piece. This is a second reason why I think BWV Anh. II 54 is the original composition and BWV Anh. II 68 is the derived composition by a somewhat less able composer.
The recording was done with the Hauptwerk software and the sampleset, made by Sonus Paradisi, of the Schnittger organ in the St. Martini-kerk, Groningen (https://www.sonusparadisi.cz/en/organs/netherlands/groningen-st-martini.html).
Score available here: http://partitura.org/index.php/johann-sebastian-bach-wer-nur-den-lieben-gott-lasst-walten-bwv-anh-ii-68
