My grandmother, summing up the impact of celebrated beauties from her Victorian youth, used to tell me, ‘People clambered up onto their chairs, my dear, just to get a look at her.’ Virginia Oldoini, Contessa di Castiglione (1837–99), sent an entire generation scrambling for similar vantage points, however wobbly, and turned it into a career. Hers is not a unique trajectory – Madame de Pompadour, Pamela Harriman and other knockout gamers of the system come to mind – but Virginia’s story plays out against one of 19th-century history’s most arresting phases, which she herself energised simply by being who God made her.

Raised in the upper echelons of Florentine society, ‘Nini’ was already a prodigy of loveliness when at sixteen her parents decided to marry her off to Count Francesco Verasis di Castiglione, a Piedmontese nobleman with a palace in Turin but never quite enough in the bank. Their union seemed doomed from the outset. The bride’s mother had witnessed the effects of her daughter’s good looks, but also knew her to have a ‘resentful, peevish disposition’ and a ‘reputation for having no feeling for anyone’. Francesco bore the brunt of this and the birth of their son, Giorgio, scarcely brought the pair closer together. The boy himself appeared winning enough, but as Benedetta Craveri, Virginia’s first modern biographer, makes clear, his role lay in amplifying her essential narcissism, ‘an ornamental appendage in the choreography devised to highlight her own beauty’.

Others more powerful saw how her assets could be used in the boardgame of international diplomacy. Having ensnared King Victor Emmanuel of Piedmont–Sardinia, the Contessa found herself becoming a key player in manoeuvres conducted by his chief minister, the wily Camillo Benso di Cavour, who unleashed her on Second Empire