17 17~ 1723, Bach is the music director in Kuideng Palace. This is the best time for him to receive treatment. Here, he can write other things besides church music and organ works. Because his master was a Protestant, Bach wrote simple hymns for the church and used them to create a large number of other church music works. He created a large number of suites, concertos, sonatas and keyboard music, both religious and secular, for teaching or court entertainment.