Separated by a 13 year age gap, Charles and Diana were at very different points in their lives when the romance between them began. Prince Charles was 32 when the couple became engaged while Diana Spencer was 19.
Prior to her engagement Diana lived with friends her own age and was working in a nursery school, while Charles was an experienced working member of the Royal Family with established passion projects. The committed environmentalist famously gave a speech warning about the risks of plastic waste all the way back in 1970.
As season five of The Crown dives into the mythology surrounding the breakdown of the former couple's marriage, here's what we know about how and why their marriage collapsed.
1981 - Diana and Charles get engaged and marry
Whilst on the surface, the budding romance between a Diana and Charles seemed picture perfect, Diana's later revelations about the early stages of their courtship and engagement paint a different scene.
The late royal collaborated with Andrew Morton on his 1992 biography titled Diana, Her True Story. After her death, a new edition was released with excerpted transcripts of the tape recordings she had made during the writing of the manuscript.
Diana is quoted as saying that even before the wedding day, she was unsure about the match. She expressed that she had concerns even then about her soon-to-be husband's relationship with Camilla Parker Bowles and told her sisters: "I can't marry him. I can't do this, this is absolutely unbelievable."
As she reached the wedding day, she said that she "had a very bad bout of bulimia the night before." She said that there was "happiness because the crowds buoyed you up" but she didn't "think [she] was happy."
However, she added: "I remember being so in love with my husband I couldn't take my eyes off him. I just absolutely thought I was the luckiest girl in the world."
1992 - Charles and Diana officially separated
In 1992, the couple separated publicly. After Morton's book was released and the public knew the real state of the Waleses marriage, further scandal was just around the corner.
In August that year, recordings of a phone call between Diana and her close friend James Gilbey were made public by the press. The phone call itself had taken place on New Year's Eve, 1980.
It further revealed the dismal perception that Diana had of her marriage to Charles and the intimacy she shared with Gilbey seemed to show she was looking for closeness outside of the confines of the Royal Family.
In December of that year, John Major announced that the couple were separating in the House of Parliament. At this stage, the palace said that divorce wasn't on the cards: Major even said in speech to the Commons that "there is no reason why the Princess of Wales should not be crowned Queen in due course."
In many ways, the conflict between Charles and Diana was only just beginning.
1995 - Queen Elizabeth orders Charles and Diana to divorce
Queen Elizabeth took matters into her own hands in 1995, when she advised the couple to draw a line under things and get divorced.
Buckingham Palace released a statement that said: "The Queen wrote to both the Prince and Princess of Wales earlier this week and gave them her view that, supported by the Duke of Edinburgh, that an early divorce is desirable."
This landmark move from the late Queen came after what was deemed the War of the Waleses, in which both Diana and Charles briefed the press against one another.
Patrick Jephson — Diana's former press secretary — wrote in his book Shadows of a Princess that "public point-scoring was one of the most unsettling aspects of marital deterioration we had to witness."
He also called the briefings from 1992 onwards "a battle" and described it as "a battle in which the Prince's legions, though numerically superior, became bogged down in a swamp of self righteousness."
Charles took part in a documentary with Jonathon Dimbleby in 1994, in which he admitted publicly that he had been unfaithful during his marriage.
A year later, Diana agreed to an interview with Martin Bashir, during which she held little back about her version of events and famously said: "there were three of us in this marriage, so it was a bit crowded," in relation to Camilla.
August, 1996 - Charles and Diana's divorce is finalised
Months after the Queen had advised them to divorce officially, the marriage legally ended.
After fifteen years of marriage, Charles and Diana went their separate ways. She could no longer use the HRH style, and was instead known as Diana, Princess of Wales.
It was only a year later when she died in a car accident in Paris at the age of 36.