John Singer Sargent was born in Florence to peripatetic American parents and trained in Paris in the atelier of Carolus-­Duran. He made his artistic debut at the Salon of 1877 with a portrait of his childhood friend Frances Sherborne Ridley Watts. Over the next few years, he exhibited a carefully selected mix of portraits – including one of Carolus-Duran – and genre paintings in the city. His daring portrait of the Louisiana-born Madame Gautreau in an off-the-shoulder black dress, entitled Madame X, shocked Paris when it was exhibited at the Salon of 1884. As Jean Strouse explains in Family Romance, the response took ‘artist and subject by surprise’.

In the wake of the scandal, demand for Sargent’s portraits fell away. He succumbed to the urgings of his fellow countrymen James McNeill Whistler and Henry James to quit Paris for London. There, ever ambitious, he pursued the same careful approach he’d adopted (at least initially) in Paris, exhibiting at the Royal Academy both genre paintings, including Carnation, Lily, Lily, Rose (1885–6), and portraits. At the 1893 Summer Exhibition, he displayed the ravishing Lady Agnew of Lochnaw (1892) and Mrs Hugh Hammersley (1892). From then on he was overwhelmed with commissions, becoming the most sought-after portrait painter on both sides of the Atlantic. Max Beerbohm drew a much-reproduced cartoon of skimpily clad beauties, well-upholstered dowagers and bellhops (sent by wealthy Americans staying at the Ritz or Claridge’s) queuing outside his studio in Tite Street to make appointments for sittings.

Asher Wertheimer, the central figure in Family Romance, would not have been among them. His father, Samson, had quit Bavaria for England in 1839, settling initially in Soho, where he declared his profession ‘gilder’. By the 1850s, the family were living in and trading from a property in Bond Street,