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

For me, the 1876 performance of Richard Wagner’s Der Ring des Nibelungen in Bayreuth was the biggest musical game changer. Wagner took on what had been, until then, the two most important pillars of music and, as others at that time recognised, he dissolved them completely.

The most important pillar was form. For us today it’s hard to hear the revolutionary aspect but he did away with what had kept every musical composition coherent. Not only form on a large scale (like aria, sonata form etc.) but the actual building blocks of music, which is phrase or period. For me, nothing that happened after that could have happened without this game change.

The other pillar was aesthetics. This was the first time that somebody had said that if a dramatic situation is excruciating or intense, then the music describing it doesn’t have to be beautiful. Aesthetics changed completely. The second act of Götterdämmerung – especially the end of the vengeance trio – represents the first time a composer had dared to compose music that makes you feel what’s going on onstage, rather than say, “How pretty that is”....