There is no cantata left to us for this week in 1723, the 18th Sunday after Trinity. It seems to be a pattern for the Trinity season of 1723 that in the week of a big holiday (St. Michael’s in this case), the cantata for the Sunday of that same week is missing. This happened as well around the holidays of St. John on June 24 and the Visitation of Mary on July 2. It is unclear what music Bach performed on the feast day of St. Michael, September 29, 1723. It might have been a cantata by Telemann, but the researchers are not sure.
Wieneke Gorter, September 24, 2016