J.S. Bach is perhaps the greatest classical composer for the organ, but he was once a young man learning from older, more accomplished teachers. Georg Böhm was that teacher, and today is his 351st birthday.
Böhm is best known for creating the chorale partita musical form, which you hear in this post and which Bach perhaps perfected. It contains several variations on a theme, something familiar to fans of Bach. It is related to both the Canon and that Fugue, and was essentially replaced by the later.