CD: Having spent several years on Thebans, which was your largest work in every respect, you turned immediately to the intimacy of writing a string quartet, a medium you hadn't touched since your teenage years. Why did you make that move?

JA: I was going from 40 staves per page to four, which was enormous fun. My first quartet, Light Music, had been premiered finally in 2013, at the Aldeburgh Festival by the Arditti. Because of that, I really felt the string quartet, as a medium, had suddenly begun to unfreeze for me, psychologically. As soon as I heard the Arditti rehearsing Light Music, I knew what I wanted to write. The project of working with the large collections of Renaissance German Christmas carols, Weihnachtslieder, went back a long time. I didn't know it would be a quartet, I just wanted to do something with all this. Some of them are still sung as carols here. ‘Wie schön leuchtet der Morgenstern’, ‘In dulci jubilo’ and things like that are well known in Britain and America, everywhere. I came across many others that are equally lovely. I studied a lot of them and made a big pitch reservoir from them. I wanted to do a piece that would explore some kind of intonation issues. Having heard that the First Quartet did actually work, I thought it was time to follow some of that up.