In Western Music there are less than five Composers that after centuries they lived, scholars, musicologists, musicians and performers unanimity coincide that every piece they wrote is unique Master Piece!
One of those composers is Johann Sebastian Bach who wrote an "almost impossible to perform" repertoire for Baroque Lute. The music manuscripts that survived have not even the smallest notation of how they were easily played in Europe by many renowned and virtuosi eighteenth century Lutenists, including Bach himself.
The question is:
Why such a pragmatic composer like Johann Sebastian Bach could wrote a so intricate and diabolically difficult repertoire for Lute that is a just a little less than impossible to play?
Nowadays, that invaluable and extensive repertoire is considered by millions of Classical Guitar performers as simply just impossible to play in modern Guitar, while this instrument has the same difficulty level, same tuning, and dimensions equivalent to the eighteenth century Lute that Johann Sebastian Bach played.