There are no conversation book entries for this date. One must conclude from the absence of entries that a) the fish luncheon party that Beethoven threw at his home for his friends before leaving for the countryside in Mödling occurred as planned around 1 PM; and b) it must have been very noisy, with everyone talking loudly enough to be heard by Beethoven; and c) it may well have continued into the evening. From Beethoven’s fondness for coffee and wine, It’s very likely that both flowed freely.
We know Franz Oliva (who was bringing salad) and nephew Karl (age 13) are there. Sunday was a free day for Karl. Since he had taken an exam the previous Thursday, May 4, which would ordinarily be a visitation day, Karl seems to have been granted an off day from his studies at the Blöchlinger Institute on Monday as well. He very well may have stayed overnight with Ludwig, since the first entry on Monday is Karl walking with uncle Ludwig to lunch. There was surely plenty of packing and cleaning up that needed to be done, and I expect Ludwig could use the help.
Other possible attendees include piano maker Matthäus Stein, who was working on developing a piano that Beethoven could hear better; and journalists Friedrich Wähner and Johann Schickh, who regularly show up in the conversation books of this period. Joseph Czerny, Karl’s piano tutor, did not attend; we later find out that since he chatted with Beethoven three days ago, Czerny came down with hepatitis and jaundice and is quite ill.
A similar lack of entries in the conversation books occurred on December 16, 1819, for Beethoven’s birthday dinner, indicating that when people were free to talk loudly, Beethoven in this period could still make out (shouted) conversations.