Ten experts decide who and what changed the course of music history.

Arnold Schoenberg (1874-1951) is undoubtedly the great innovator in 20th-century music. Of course, if you simply follow the so-called rules he set out in his Harmonielehreof 1910 it’s pretty boring. Every part needs a rule, a system, law and order. It was left to Schoenberg’s genius to break out of these constraints and really use the 12-tone system to make great music. Of course later on, certain followers of Schoenberg became a little bit limited in their emotional and artistic approaches to this kind of music. In other words, some of his followers have led his methods into a dead end.

I’ve conducted a lot of Schoenberg: I do the Five Pieces, Op. 16, a lot. I’ve also conducted Moses and Aaron, one of the greatest operas of the 20th century. I conducted the Piano Concerto – a very important work – but I also did a lot of the early pieces: the Songs, Op. 8 and the Kammersymphonie. One of the greatest things about Schoenberg was that he never denied his 19th-century roots.

Of those who came after him, I love Webern as well, only it’s very hard to...