NOT my words but those of the eminent Bach scholar Arnold Schering, written some 90 years ago. While ‘monumentality’ may be less prevalent today, the ‘continuously choral scoring’ to which Schering objected is still routinely promoted as Bach's own preferred practice. In this, the Mass in B minor differs not at all from the composer's other church works. Yet, in common with an overwhelming majority of those works, early sources for the Mass contain no suggestion whatsoever of any requirement for ripieno singers. (A brief reminder: the ripienist's role was to reinforce – not to replace – the concertist in choral movements.) Both in the composer's autograph score of the complete Mass and in the set of parts of the Missa prepared for Dresden, vocal tutti indications are entirely absent; moreover, neither this set nor that associated with C. P. E. Bach's 1786 Hamburg performance of the Credo – both apparently complete (with 21 and 20 parts respectively) – includes any copies for ripienists. This conspicuous absence of direct evidence for vocal ripienists necessarily forms the starting-point for the present investigation.

DESPITE its unique (if problematic) status within Bach's output, the Mass in B minor has proved fertile ground for previous exploration of the composer's choral writing and its implied mode(s) of performance. Indeed, Joshua Rifkin's searching reassessment of the nature of Bach's choir was for some time widely perceived to relate almost exclusively to the Mass through his recording of the work, even though his original 1981 paper had barely made any mention of it. In the same year, however, the Austrian-born American conductor Erich Leinsdorf specifically challenged (albeit in a much broader context) ‘the customary division of Bach's B minor Mass into sections for full chorus and for soloists’: