Contrapunctus 1 from the Art of Fugue (BWV 1080) was composed in 1748 - 1749 and published after Bach's death in 1750. The Art of Fugue was composed in SATB open score format - no instruments were specified in the manuscript or in subsequent engravings which has made it very attractive and inviting to arrangers for years.
 
Contrapunctus 1 is an example of simple fugue. Originally in D minor, scored here in C minor.