Bach’s ambition to compose a body of ‘well-regulated church music’ – liturgical music for the entire church calendar – produced a wealth of sacred cantatas. Around two hundred have survived, and are an eloquent expression of his opinion that ‘true music should be for the honour of God and the recreation of the soul’. That comment – made with respect to the art of realising a figured-bass (where harmony is indicated by numbers) – seems appropriate to this collection, since the choice of these glorious works was influenced by a consideration of number symbolism and other extra-musical devices. That this most cerebral music touches the emotions so keenly might seem a paradox, but as a performer, analysing the possible thinking behind Bach’s musical decisions brings the composer closer.
Behind the unmatched contrapuntal intricacy of Bach’s music lie yet further layers of complexity, his compositional choices being prompted by the demands of symbolism of various kinds, rhetorical and numerological. Since ancient times, simple proportions had been understood to lie at the heart of musical sound. Mediaeval musicians, finding perfection in the Trinity, developed systems of notation accordingly, with the outcome that triple time was considered tempus perfectum; duple time imperfectum. Given that metre is such an evident characteristic of any music, and since triple time is something that – for us bipeds – will always be a dance, this central tenet of Christian doctrine had considerable (and possibly unintended) consequences for the character of sacred music. Bach, in addition to references to the Trinity (3 and its powers 9 and 27) and Christ’s age (33), also gave significance to numbers derived from his own name (BACH=14, 41=JSBACH, where A=1, B=2 etc.). Since composition apparently cost him comparatively little effort, ‘recreation’ for Bach’s soul seems to have lain in a delight in such convolutions; but whether as compositional spur, marks of devotion or for his private satisfaction, we can only speculate.