Gene Veith in his review (Bach’s smackdown) of An Evening in the Palace of Reason: Bach meets Frederick the Great in the Age of Enlightenment shares a interesting collision between self-assertion and beauty for God’s sake:
In 1747, Frederick the Great–the king of Prussia, patron of Enlightenment rationalism, and military strongman–invited Johann Sebastian Bach, now an old man three years from his death, for an audience. Frederick fancied himself a musician and scorned the old-fashioned polyphony that Bach was known for in favor of music with a single pleasant melody. Frederick, who enjoyed humiliatating his guests, had composed a long melody line full of chromatic scales that was impossible to turn into a multi-voiced canon (that is, a “round”: think “Row, Row, Row Your Boat” with different groups starting at different times) and told Bach to turn it into a fugue (an even more complicated “round”). Whereupon Bach, on the spot, sat down at one of the new piano fortes and turned it into a three-part fugue. The flummoxed King said, in effect, OK, turn it into a 6-part fugue. A few days later, Bach sent him a 6-part fugue and more than a fugue, “A Musical Offering” that rebuked Frederick and all of his Enlightenment notions with the Christian faith.