Harriet Constable is an English documentary filmmaker and journalist. The Instrumentalist is her first novel – thanks, perhaps, to a musical childhood. As a reporter for the Financial Times, she travelled the world. She worked on news production for the BBC as part of the BAFTA-winning team behind 9/11: Inside the President’s War Room, and much else besides. That eclectic background makes her choice of Anna Maria della Pietà as a subject for historical fiction both logical and a canny one – evident from the opening pages.

In 1696, an impoverished Venetian prostitute gave birth to a girl. Days later, she placed the child in a designated slot in the wall of an orphanage, the Ospedale della Pietà, whose specialty was a musical education for its children. It was the best she could do for her infant. Into the baby’s blanket she slipped half a playing card (she kept the other half) and a note, written for her by a disapproving scribe: “. . . know you were loved.”

From such wretched beginnings, the baby girl not only survived, but showed such talent that by the age of eight, she was a violin virtuoso and proficient on a half-dozen instruments. The orphanage’s...