Gladys Deacon's childhood dream to marry a duke came true
It was the 1960s and Conservative politician Sir Henry 'Chips' Channon was perusing a jewellery shop when he noticed a strange old lady.
It dawned on him that he was looking at Gladys Deacon, Duchess of Marlborough, who he described as once being the world's most beautiful woman.
But as he went to say hello she dropped everything and fled from the shop.
When teenager Hugo Vickers read the extract recounting this event in one of Channons' diaries it set off the start of an obsession.
Mr Vickers decided that he would find out what had happened to the American beauty who had been the toast of European society at the turn of the century.
He told the BBC: "I went to Blenheim aged 16 in 1968 and I asked the guides about her.
"They said 'We don't talk about her.'
"It hadn't occurred to me that the reason she had disappeared was she was in fact in a psycho-geriatric hospital.
"I eventually tracked her down there and was allowed to go see her. I made friends with her and talked to her."
A new exhibition at Blenheim Palace now seeks to bring Gladys Deacon's legacy back into the public eye decades after she was unceremoniously evicted from the palace grounds.
The property is still filled with reminders that she once lived there.
She was famed for her blue eyes which were painted on the portico ceiling in front of the main doors, by instruction of the 9th Duke of Marlborough.
She has also been immortalised as two matching stone sphinxes in the Lower Water Terraces and a lone photograph of her is framed in the Palace State Rooms.
But though she would live a life of glamour, the young Gladys' life was steeped in scandal.
Her father shot her mother's lover dead in 1882 when Gladys was 11. Soon after her mother kidnapped her from a convent, fearing her father would gain custody of her.
At 14 she read about Consuelo Vanderbilt's engagement to the Duke of Marlborough and declared that she would one day catch herself a duke.
"I am too young though mature in the arts of woman's witchcraft," she proclaimed.
Luckily for her the duke and his new duchess were in a loveless marriage. Whilst the Vanderbilt family were looking for added status for their daughter, the duke was only interested in her millions.
By this time Gladys had been living a Bohemian life in Paris. But the course of her life would change forever when the duke invited her to Blenheim Palace in the late 1890s.
Gladys became friends with Consuelo and whilst staying at the palace another house guest, the Crown Prince of Prussia, became smitten with her.
According to Mr Vickers: "He took one look at her and fell madly in love with her.
"When they were driving to Oxford in a carriage he kept turning around to the consternation of everybody, in order to gaze at Ms Deacon sitting in the back seat."
But Gladys only had eyes for the duke.
At 22 she had wax injections in an early cosmetic surgery attempt, which had a detrimental affect on her famous good looks.
Eventually, Consuelo left the duke but did not grant him a divorce for some time.
But when she did it meant that Gladys, who had been the duke's mistress for some time, had her childhood dream come true.
They married in Paris in 1921. She was now 40 years old and had known him for over 20 years.
"I married a house not a man," she was quoted as saying.
Gladys became Duchess of Marlborough in 1921 at 40 years of age
In a letter to the duke she wrote: "Am I not the last of the Marlborough gems? Greek in temper with a more modern dash about certain parts?"
That infamous temper soon came to the fore and the duke and his wife started to drift apart as her behaviour became more erratic.
Mr Vickers explained: "At one point she came down to dinner and placed a revolver on the table.
"The next guest to her asked what it was for and she said, 'Oh I don't know, I might just shoot Marlborough.'"
The duke found her increasingly difficult to live with. In 1933, after losing patience with her hobby of breeding Blenheim Spaniels, he fired her staff and evicted her from the palace.
He died soon after and Gladys' swift fall from grace followed. In Mixbury near Brackley she tipped a bucket of water over a journalist's head.
Gladys shut out the outside world, surrounding herself with a multitude of pets.
Mr Vickers said: "She did become a complete and absolute recluse.
"I imagine that through her head were floating the most fantastic memories of Paris and Rome and Italy and all the wonderful people she'd known.
The duchess' behaviour became more erratic as time went on
"But eventually it probably became too much for her and she became a scary person. She was threatening to shoot people who stole apples from her orchard and was ringing people in the middle of the night.
"She was still very intelligent and whilst sitting in this reclusive atmosphere she was reading the newspaper, keeping diaries, noting what was going on in the world and was as shrewd as anything."
Gladys was eventually incarcerated in the psychiatric hospital where she would spend the next 15 years.
That was when Hugo Vickers first met the lady he describes as the most fascinating person he has ever met.
"It's extraordinary for me to have met her in 1975 when she was born in 1881," Mr Vickers said.
"There came a day once when my son came from school aged 7 having copied the Haystacks by Monet.
"I said to him that I had a friend who knew Monet and sent him into school the next day with a photo she'd taken of Monet in his garden at Giverny.
"So there is a lovely link there which in a way goes back."
Gladys Deacon died in the hospital in 1977. She was 96 years old.
Hugo Vickers is an author who has written several books about 20th century figures, including 'Gladys, Duchess of Marlborough' (1979).