As the daughter of America’s second-richest man, Huguette Clark was born into phenomenal privilege, with luxury homes on both the east and west coasts, and the social life of a debutante who came of age in the Roaring Twenties. Yet by the time she died in 2011, at the age of 104, Ms Clark had lived as a recluse for more than half a century, and spent her final 20 years confined to a New York hospital room. When she divvied up her $300m fortune, she left it not to her surviving relatives, but to the few people who cared for her in her last decades.

Now, 20 distant family members – most of whom she never met – are challenging the will in court, claiming that the centenarian multi-millionairess was coerced into composing it by her beneficiaries. Next week’s trial in Manhattan, for which jury selection is due to begin on Tuesday, centres on two wills, reportedly written six weeks apart in 2005.

The first left Ms Clark’s fortune to her family. The second, however, left 75 per cent to charity and the remainder to her goddaughter and a handful of medical and business employees. “I intentionally make no provision in this, my last will testament, for any members of my family, having had minimal contacts with them over the years,” the document reads.

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Ms Clark was born in Paris in 1906, the younger daughter of the industrialist and US Senator William Clark and his second wife. The relatives challenging her will are descendants of Clark, a copper mining and railway magnate, and his first wife. In 1928, Huguette married the son of one of her father’s business associates, but divorced a year later, having had no children.

In the subsequent decades, despite owning several magnificent homes, she became increasingly reclusive and stayed in a single candlelit room in her Fifth Avenue apartment. According to Empty Mansions, a new book co-written by a Pulitzer Prize-winning journalist, Bill Dedman, she was a virtual hermit until 1991 when, at 85, she was forced to admit herself to New York’s Beth Israel hospital with facial skin cancer. According to the notes of her doctor, Henry Singman, Ms Clark “resembled an advanced leper patient”. After surgery, she refused to be discharged and stayed there under a pseudonym, paying for private care for the rest of her life.

She was randomly assigned a nurse, Hadassah Peri, who became her closest companion, and spent 12 hours a day at her side for the next 20 years. In return, Ms Clark gave Ms Peri and her family $31m in gifts in her lifetime, and about $30m in her will. Dr Singman, to whom Ms Clark left $100,000, has given up his inheritance so that he can testify freely in the will’s defence.