text: At the time only men sang in church: high pitch vocal parts were usually performed by treble choristers. In 1730, Bach informed the Leipzig Town Council as to what he saw as the number of singers that should be available for the churches under his responsibility, including those for the St. Thomas Church: a choir of twelve singers, plus eight singers that would serve both St. Thomas and the Peterskirche. The request was only partially granted by the Town Council, so possibly at least some of the Passion presentations in St. Thomas were with fewer than twenty singers, even for the large scale works, like the St Matthew Passion, that were written for double choir.
  In Bach's time, St. Thomas Church had two organ lofts: the large organ loft that was used throughout the year for musicians performing in Sunday services, vespers, etc., and the small organ loft, situated at the opposite side of the former, that was used additionally in the grand services for Christmas and Easter. The St Matthew Passion was composed as to perform a single work from both organ lofts at the same time: Chorus and orchestra I would occupy the large organ loft, and Chorus and orchestra II performed from the small organ loft. The size of the organ lofts limited the number of performers for each Choir. Large choruses, in addition to the instrumentists indicated for Choir I and II, would have been impossible, so also here there is an indication that each part (including those of strings and singers) would have a limited number of performers, where, for the choruses, the numbers indicated by Bach in his 1730 request would appear to be (more than?) a maximum of what could be fitted in the organ lofts.
  Later revisions and performances (BWV 244.2, previously 244)