 An anecdote from Mozart's time suggests that the composer himself was very impressed with his sister-in-law's performance.The story comes from an 1840 letter from composer Ignaz von Seyfried, and relates an event from the last night of Mozart's life—4 December 1791, five weeks into the opera's initial (very successful) run.According to Seyfried, the dying Mozart whispered the following to his wife Constanze