In an interview on Classical Music

Quite important to the direction of 20th century music?

Yes, definitely, and that’s also why I chose The Bach Choir by Andrew Parrot. It’s detective work in some ways, dealing with the hugely contentious issue of how many people Bach wanted to sing in his great choral works: the Passions and the B Minor Mass. This may seem a very esoteric subject, but manuscripts like this essentially seem to blow away all received wisdom on how we should hear Bach. He goes through various written sources, iconographical sources, scientific analyses of acoustics and various other things to argue that Bach did not want a large choir. He most likely wanted the four soloists to sing throughout the St Matthew Passion, which is a huge task: it’s three hours long.

The book also brings out some brilliant detail, like the fact that boys’ voices used to break much later then ­– on average at around 17 or 18 ­– and this radically changes our idea that you can have these moving arias being sung by eight- or nine-year-olds. It’s always struck me as preposterous to do that – you have to have someone who’s had at least some understanding of what it is to be an adult. It’s a convincing argument that totally transforms how you have to do the Passions, so it’s a very important book in the sense it can radically change our view of some of the greatest musical works. It brings up the age-old argument of whether one follows the composer to the letter, or goes with the maestro – the interpreter of these works – and in the early 20th century the conductor often saw themselves as above the composer and what they wanted.