Tales of tyrannical conductors are legion, but the granddaddy of them all was Gustav Mahler. A small man, coming in at just five foot and four inches, there were contemporaries who put Mahler’s hyper-demonstrative style down to a sense of physical inadequacy.

Mahler Caricature of Gustav Mahler

Others sensed the fanaticism of the composer, determined to honour the music above all else. Whichever was the case, as a maestro, Mahler set the trend for many who were to follow.

In the pit, he was a conductor in the Beethoven mould, all arms. “His body was racked with movement and in the semi-darkness he looked like some kind of fairy-tale goblin engaged in a flurry of hocus-pocus,” wrote the critic Ernst Décsey. “In the harsh spotlight his face was fascinatingly ugly and had a ghastly pallor. Every little shift in the orchestra was reflected in his sensitive features… it was a case of both devils and angels crossing his visage in turn.”

Mahler’s attitude towards musicians could be dismissive. “Do you think these people are interested in learning and making progress?” he wrote to a friend. “For them, art is only the cow which they milk so...