I've just received an assignment to review a performance of Mozart's Requiem this weekend. Now, I've heard Mozart's Requiem in performance at least three times, but I never paid close attention to what was going on in it. Time to do so. So I fetched out B's old vocal score (of course she has one, and there it is next to Brahms's Requiem and Verdi's Requiem) and followed along with a recording. I like what he does with matching up the soloists, especially in the Tuba Mirum where each successive solo entrance stomps on the last note of the previous one.
But I was also curious if I could tell from ear alone where Mozart stopped. As we all know from Amadeus, Mozart didn't live to finish the piece, but Salieri had nothing to do with it. The work had been commissioned, and Constanze was anxious that the patron not find out that Wolfie hadn't finished the job, or she might not get paid. So she hastily enlisted a handy composing friend (possibly a student of Mozart's, or maybe she made that up) named Süssmayr to quickly finish up the work in secret.
Besides the fact that it's somewhat windier? Yeah, there's a couple of things.
First: "Hosan-NAH." Süssmayr! Who pronounces it that way?
Second: A moment just before the end of the Agnus Dei. Mozart would never spiral down into a mere half-cadence that way. It's just not him.