The two organ pieces by Johann Sebastian Bach published here are not part of his known organ works. Fantasia C-Dur BWV 573 is a fragment originally, completed by Hans-André Stamm. View page 1 pdf
Sinfonia D-Dur is originally composed for violin solo and was later transcribed by Bach for organ with accompaniment through strings, 3 trumpets and timpani forming the introduction of cantata no. 29. Stamm’s arrangement of this movement represents an optimal compromise: it reduces the technical performing difficulties, which signifies the known available arrangements, reducing the chord accents of strings and brass of the orchestral part especially in difficult passages of the right hand in the sense of the original violin solo version, resulting in a more transparent sonority. View page 1 pdf
Videos on Youtube:
Fantasia C major BWV 573
Sinfonia D major from Cantata No. 29