Bach's B minor Mass was an inchoate collection of movements at the time of his death. Parts of it had been performed, most of it hadn't, and the complete score didn't get published for another century.
And it wasn't until 1968 that Nikolaus Harnoncourt and the Concentus Musicus Wien recorded it for a major German label with actual period instruments in a reading that played a central role in the historical performance movement.
We'll have the Harnoncourt perfomance of the B minor -- the way Bach wrote it and intended it -- as our sole work this week.