Why do so many conductors of early music ensembles insist on leaping up and down in front of orchestras and choirs, waving elongated pieces of wood, and poking their interpretative noses into everything from entries, phrasing, and often the tiniest nuances of musical expression? Handel didn’t do it, nor did Purcell, Arne, Boyce or pretty much anyone in Britain until the 1830s. In fact, when you see a formal portrait of a composer of musician from the period clutching a rolled-up piece of manuscript paper, more often than not this isn’t meant to signify one of his divine masterworks. It is in fact the tool of his trade with which he would beat time: up-down, one-two, and nothing fancier than that.

Peter Holman...