Canonic Variations on "Vom Himmel hoch da komm' ich her"
Bach composed the piece when he became a member of Mizler's Music Society in Leipzig in 1747.  It was printed in 1747.  Another version was published later.  This was an autograph manuscript which also included other organ music: the six trio sonatas  and the Great Eighteen Chorale Preludes.  The most important difference Bach made in this version is that the fifth variation was moved to the middle.