Complex sentence: The oldest copy comprises only of an early, two bar shorter variant of the Fantasia, and comes from Bach's pupil Johann Tobias Krebs and was created after 1717, which is close to the time of origin.
Split into simpler sentences: The oldest copy comprises only of an early, two bar shorter variant of the fantasia. It was written by Bach's pupil Johann Tobias Krebs and was created after 1717, close to the time of origin.