Publisher Adolph Martin Schlesinger writes to Beethoven today, according to the registration mark on Brandenburg Letter 1431 (dated June 10, 1821). Unfortunately, today’s letter is not known to survive, and its contents are unknown for certain, although we can hazard some educated guesses. Letter 1431 was Beethoven’s letter talking about the initial corrections to the piano sonata op.109, so Schlesinger’s response almost certainly related to the proof correction process. Since Beethoven had promised in that letter that he would send the corrections no later than June 15, Schlesinger may have been writing to note that he had as of yet received nothing. Of course, Beethoven did not send the corrections until yesterday, July 6.