King Charles' affair with his now-wife, Camilla Parker Bowles, has been common knowledge for decades, and much was previously made of her transition from mistress to Queen.
But far less has been reported about his supposed second mistress, Lady Dale 'Kanga' Tryon, who died just months after his first wife, Princess Diana, in mysterious circumstances.
Once described as "the only woman who ever understood Charles", Dale was a socialite in British royal court circles and a successful businesswoman in the fashion world.
Born in 1948 in Melbourne, Australia, to a wealthy middle-class family, Dale moved to London in 1972, where she met her future husband, Anthony Tyron, 3rd Baron Tryon.
Dale became friends with Charles through Anthony, who was one of his closest pals during the 1970s and 1980s.
According to a 2008 documentary, Prince Charles' Other Mistress, Charles was already seeing Camilla, who was married to Andrew Parker Bowles, when Dale caught his eye.
Charles was apparently as smitten with Dale - who he nicknamed Kanga - as he was with Camilla. And when the Baroness gave birth to a child with her husband, she named her son after Charles and even made him godfather.
The single Prince allegedly jumped between Camilla and Dale, who are said to have been sworn enemies. The supposed love triangle only came to an end when Charles married Diana.
Dale reportedly began to understand the power that came with being a mistress of the future monarch, and utilised it to drum up publicity for her 'Kanga' fashion line.
It's believed that Dale became Diana's friend and Camilla's enemy - with the Princess even wearing one of Kanga's designs in 1985.
But while she reportedly remained in love with Charles, it was Camilla he chose to restart his affair with.
Sadly, Dale's health then deteriorated with the re-occurrence of her childhood illness, Perthes' disease, and a diagnosis of uterine cancer in 1993.
In 1996, Dale checked herself into a rehabilitation clinic after becoming addicted to painkillers given as part of her cancer treatment.
While she was there, she plunged nearly eight metres from a window, shattering her spine and becoming paralysed from the waist down.
Dale insisted that she was pushed - with friends stating that she believed someone was trying to kill her - while others thought she had jumped.
Afterwards, her husband had her sectioned under the Mental Health Act and filed for a divorce.
She is said to have remained hopelessly in love with Charles and was reportedly seen pursuing the royal in her wheelchair at a polo match in July 1997.
In return, Charles is said to have issues a statement distancing himself, stating that while they spoke 'once or twice a year', they were no longer close friends.
In November 1997, Dale contracted septicaemia after a holiday abroad and died shortly before her 50th birthday, just months after Diana was killed in a Paris car crash.
A decade later, the story of her supposed love affair with Charles resurfaced - though the Tryon family consistently denied the claims.
