Choral timeline

In the Lutheran Germany of Bach's time, the musical menu for church services could be long and elaborate (just like the services themselves - which often lasted several hours!). Cantatas (substantial multi-movement pieces, effectively "sermons-in-music", which might use soloists and a large complement of instruments, as well as chorus) were sung at most services, and smaller-scale works - motets - were sung as introits for services and for certain special occasions.

In 1730, whilst Cantor at St Thomas Church, Leipzig, Bach sent a memo to the City Council describing his ideal requirements for church music. As well as saying how many singers there should be and of which voices, he goes on to explain the differences between the roles. Cantata singers who formed the major part of Lutheran services were skilled musicians; motet singers needed less skill; and chorale singers (who performed only the chorales - or Lutheran hymn-tunes) didn't need much musical knowledge at all. But although the general repertoire of motets used in the Lutheran services did not require much skill, Bach's own motets were more advanced, so he employed dedicated Concertisten (soloists).

This, the longest of his six surviving motets, was composed for a memorial service for Johanna Maria Kees in 1723. Its 11 movements, which switch between biblical text and the words of a chorale by Johann Franck, demonstrate perfectly different techniques for treating musical material.

There is a clear symmetrical form to the piece as a whole, with the music in these two movements mirroring almost exactly the material in the closing ones, while all the outer movements frame a substantial fugue which lies at the centre of the work and the heart of its theological message.