The secularisation of society, therefore, brought about the sacralisation of music. Those intense feelings of communion which in Bach's Leipzig were directed towards the unseen presence at the altar were, by the mid-19th century, directed by silent, swooning audiences towards Liszt, as he sat God-like above them.

When Wagner created his theatre at Bayreuth, it was with the express purpose of presenting "sacred" works of art such as Parsifal and Tristan and Isolde - works saturated with religious emotion, neither of which mentions any God (other than the one that can be heard in its harmonies).

The evolution of music has, therefore, been profoundly affected by secularisation, and by its immediate consequences, such as nationalism and democracy. Moreover, as Blanning shows in pages as erudite as they are lucid, technology fed into the sacralising process. The demon figure of Paganini, with his technological virtuosity, already sent shudders down the spines of early 19th-century audiences. Then the invention of the piano put the entire classical repertoire for the first time within reach of one pair of hands. The domestic pianist could play arrangements of the symphonies and overtures that her listeners might never hear in the concert hall, and in doing so transform herself into the real presence of the composer, who spoke directly and intimately to the company at home. From Jane Austen to DH Lawrence, novelists have described the seductive power that the piano bestowed, raising the emotional stakes after dinner to a point never recorded in the days of the harpsichord. I would add that the CD player and the iPod are agents of seclusion rather than seduction.