#1) Identify a contemporary event that is connected to a musical piece.
Answer: He spent the last months of his life in a darkened room, revising his great chorale fantasias (BWV 651-668) with the aid of Altnikol, his pupil and son-in-law. It was in these circumstances that he composed his last chorale fantasia. Apparently he left this work unfinished till his death making it possible for the Art of Fugue theme to fit.
I hope it helps, Regards.