True: The Queen had cousins living in a psychiatric hospital.

In 1987, news that two of the Queen’s cousins were living in a psychiatric hospital broke.In season four of “The Crown”, an episode titled “The Heredity Principle” delves into a Windsor family secret. The episode depicts the institutionalization and subsequent abandonment of two of the Queen’s first cousins, Katherine and Nerissa Bowes-Lyon, who, owing to their developmental disabilities, were hidden from the public and declared legally dead. In 1987, the news that two of the Queen’s cousins were living in a psychiatric hospital broke. Katherine and Nerissa Bowes-Lyon, who both had a mental age of about three years old and never learned to talk, were the third and fifth daughters of John Herbert Bowes-Lyon, the brother of the Queen Mother, and his wife, Fenella Bowes-Lyon. In 1941, when Nerissa was 15 years old and Katherine was 22, they were sent from the family home in Scotland to Royal Earlswood Hospital at Redhill in Surrey, where they lived out the rest of their days. In a 2011 Channel Four documentary titled “The Queen’s Hidden Cousins”, careworkers at Earlswood testified that whenever members of the royal family appeared on television, the Bowes-Lyon sisters would stand up and salute or curtsy. In 1963, the Bowes-Lyon family reported to Burke’s Peerage, the guidebook to the British aristocracy, that both of the sisters had died, Nerissa in 1940 and Katherine in 1961. However, in reality, Nerissa would die in 1986, and Katherine in 2014. Moreover, further investigation into the matter revealed that not just two but five of Queen Elizabeth’s cousins were hidden away in the hospital. While the episode shows the Queen Mother knew about her nieces and left them in the hospital in the name of keeping the bloodline pure, little is conclusively known about the Royal Family’s knowledge or complicity in the trajectory of the Bowes-Lyons sisters’ lives.