Bach Sinfonia 15; BWV 801

Inventions and Sinfonias (Bach)

The Inventions and Sinfonias, BWV 772–801, also known as the Two- and 

Three-Part Inventions,  are a collection of thirty short keyboard compositions
 by Johann Sebastian Bach (1685–1750): 15 inventions, which are 2-part 
contrapuntal pieces, and 15 sinfonias, which are 3-part contrapuntal  pieces.
 They were originally written as musical exercises for his students.

The two groups of pieces are both arranged in order of ascending key, each group
covering eight major and seven minor keys. 

The inventions were composed in Köthen; the sinfonias, on the other hand, were
probably not finished until the beginning of theLeipzig period.