Warning: Spoilers for The Crown season 4 are ahead.
Season 4 of The Crown marks the start of the story every British royal family fan has been waiting for: The Princess Diana years, from her engagement to Prince Charles to the dissolution of their tumultuous marriage. That's the story many viewers already know, but The Crown's reimagining also delves into deeper family secrets, namely the heartbreaking, seldom-told tale of Katherine and Nerissa Bowes-Lyon, the Queen’s developmentally disabled cousins who were institutionalized in the mid-20th century.
The Crown’s fictionalized version of Nerissa and Katherine's story finds Princess Margaret (Helena Bonham-Carter) and Queen Elizabeth II (Olivia Colman) looking for answers about their cousins’ whereabouts, as both were told long ago that Nerissa and Katherine had passed away. But for the most part, the story centers more on Margaret and how she is affected by the news that they were not in fact dead, but hidden away at a mental hospital. This revelation confirms to the recently demoted royal that her family is made up of cruel, callous people — and that she was not the only one affected by their choices. The series does not go into much more detail about the hidden sisters, but the neglect of both women is more than motivation for Margaret: it's a dark mark on the real royals' history.
In real life, according to The Independent, Nerissa and Katherine were born in 1919 and 1926, respectively, to John Herbert Bowes-Lyon and his wife, Fenella. John Herbert was the brother of the Queen Mother, also known as Queen Elizabeth and Princess Margaret’s mother, making Nerissa and Katherine the first cousins of the Queen.
Both sisters were born with developmental disabilities, including the inability to talk, and, after being clinically diagnosed in 1941 as “imbeciles,” per The Telegraph, Katherine and Nerissa were secretly placed in Royal Earlswood Hospital, a Surrey mental hospital, and essentially left there to live out their days. The Guardian reports that neither woman had any record of visitors during their time at Earlswood, and they didn't receive any money from their family beyond the normal charity amounts the royals gave to Earlswood.
Interestingly enough, The Independent also reports that three cousins from Nerissa and Katherine's mother's side — Rosemary, Idonea, and Etheldreda — also had similar disabilities and lived at Earlswood. According to The Tab, in 1987, genetic experts determined that all five of these women potentially had a genetic disorder that caused disabilities in the female members of the bloodline on their mother's side.
In 1963, Burke’s Peerage — a who’s who of genealogy of the global elite classes and likely the book the royals consult on The Crown — suddenly noted that both Nerissa and Katherine had passed away in 1940, though they were both alive and well. Was it a cover-up? A mistake? In The Crown, the fictionalized Queen Mother admits she knew all about Nerissa and Katherine's institutionalization, but did nothing about it so that her bloodline would seem "pure." Beyond the cruel connotations of the explanation, what that essentially means is that the Queen Mother was trying to prevent anyone having a reason to dispute her husband, George VI, taking the throne after his brother, Edward VIII, abdicated.
In reality, Burke's Peerage did issue a retraction on their deaths. Per Esquire, in 1987, Lord Clinton, a relative of Nerissa and Katherine, said that because Fenella, their mother, was "a vague person," the marking of both women as deceased was an accident. "I don't think there is any more to it than that," he told the Glasgow Herald at the time. "It was forgetfulness. I really don't know. I don't think anybody will ever know. I don't think it was a cover-up."
Whatever the reason for their fate and its record, the carelessness with which these women were treated is heartbreaking.
Nerissa died in 1986 at the age of 66, according to The Independent, buried in a simple grave with just her last name and patient number on a marker — that is, until the royals stepped in and gave her a proper headstone. A year after Nerissa's death, in 1987, the world found out about the sisters, thanks to a reporter from The Sun who posed as one of Katherine's relatives to photograph her in the hospital. Public outcry was fierce against Buckingham Palace, who would not comment publicly on the women and said it was a matter for the Bowes-Lyon family to address. Katherine died in 2014, ending yet another sad chapter for the British royal family.