Princess Margaret was second-in-line to the throne behind her older sister, Queen Elizabeth II, and she became one of the best-loved royals worldwide.
When Diana married Charles, she and Princess Margaret became neighbors at Kensington Palace, and Princess Margaret helped Diana transition into royal life.
However, once Princess Margaret felt that Diana had betrayed the royal family, she was furious and upset. Here's a look at their relationship and her reactions to Diana's betrayal.
THE LIFE OF PRINCESS MARGARET
On August 21, 1930, Princess Margaret was born at Glamis, Scotland. She was the younger sister of Queen Elizabeth II. She was third in line for the throne and the second daughter of the Duke and Duchess of York.
After her uncle abdicated the throne, her father became King George VI, making her second in line. She and her sister grew up in the public eye even though it was suggested to their parents to send them to Canada during World War II.
Portrait of Princess Margaret and then Princess Elizabeth on April 17, 1940 | Photo: Getty Images
In her youth, she was called a free spirit as she was attractive and fun-loving. Once her sister got married, she became one of the most eligible single women globally.
Even though everyone loved her, she was unlucky in love as she fell in love with a divorced Battle of Britain hero, Group Capt. Peter Townsend of the Royal Air Force.
There were objections to their relationship as the Church of England forbade divorce and her sister, being Queen, was the supreme governor of the Church.
Portrait of Princess Margaret | Photo: Getty Images
Eventually, the Queen's 'rebel sister,' whose private life became the subject of intense media speculation, bowed to the demands of a moral code. In May 1960, she married a photographer, Anthony Armstrong-Jones.
Princess Margaret's marriage with Armstrong-Jones lasted for 18 years before they divorced, and till her death, she did not remarry.
Princess Margaret and her new husband Antony Armstrong-Jones leave Westminister Abbey after their wedding | Photo: Getty Images
DIANA BECOMING A PART OF THE ROYAL FAMILY
Diana was 16 when she first met Prince Charles at the Spencers' ancestral home of Althorp in 1977. He was 29, was visiting to participate in a pheasant shoot, and was dating her older sister, Sarah.
They met again in 1980 at the home of one of his friends, and he was no longer dating her sister. He was infatuated with Diana and invited her to spend some time with his family at Balmoral in November 1980.
In February 1981, Prince Charles asked for her hand in marriage, and five months later, they got married at St Paul's Cathedral on July 29. Their wedding was a lavish ceremony, which many called the "wedding of the century."
Princess Diana and Prince Charles wave to onlookers from the balcony at Buckingham Palace just after their wedding | Photo: Getty Images
Once Princess Diana became a part of the royal family, people quickly pointed out her similarities with Princess Margaret. They both had countless celebrity friends and were neighbors at Kensington Palace.
Princess Margaret was said to have "put her arm around Diana" and taken her under her wings. They would shop together, visit the theater and even attend social engagements in each other's company.
Even though Princess Margaret was an early Diana fan and asked her sister to cut Diana some slack, she still put her sister's needs above all else. She proved this in 1992 when the Queen had a horrible year.
Princess Diana And Princess Margaret Attending James Ogilvy And Julia Rawlinson Wedding At St. Mary The Virgin Church Saffron Walden on July 30, 1988 | Photo: Getty Images
In March of 1992, the Duke and Duchess of York announced their separation. In April, the Queen's daughter Princess Anne got divorced from Captain Mark Phillips, and in November, there was a fire at Windsor Castle.
The year ended with the separation of Prince Charles and Diana in December 1992. Princess Margaret suggested an early divorce for Prince Charles and Diana to save the monarchy.
Princess Margaret, Countess of Snowdon, Diana, Princess of Wales, and Sarah, Duchess of York, on the balcony at Buckingham Palace on September 15, 1990, in London | Photo: Getty Images
When Prince Charles and Diana were engaged, Princess Margaret was delighted, but she knew about his relationship with Camilla, the Duchess of Cornwall. When a friend asked her about the engagement, she said,
"We're extremely relieved – but she [Camilla] has no intention of giving him up."
Prince Charles had first met Camilla when he was 24 and fell head over heels for her, but the royal family considered her an inappropriate match for the future king.
Lady Diana Spencer with her fiance Prince Charles and Princess Margaret at the wedding of Nicholas Soames and Catherine Weatherall at St. Margaret's Church, Westminster, London, June 4, 1981 | Photo: Getty Images
THE END OF DIANA AND PRINCESS MARGARET'S RELATIONSHIP
In 1995, after Diana had an interview with Panorama host and journalist Martin Bashir, Princess Margaret was furious. She sent her a letter indicating that Diana was incapable of making the slightest sacrifice.
Diana's brother, Earl Charles Spencer, introduced Diana to Bashir after Bashir allegedly used falsified bank statements to convince him that information about Diana was about to be leaked by two royal courtiers.
Diana, Princess of Wales, watches Trooping the Colour with Prince William, Prince Harry, Lady Rose Windsor, Lady Davina Windsor, and Princess Margaret from the balcony of Buckingham Palace | Photo: Getty Images
In the interview, Diana admitted that she had an affair, that Prince Charles's affair made her feel worthless, spoke about having bulimia, suggested her husband might not be able to adapt to being king, and more.
After the interview, Diana was devastated that Princess Margaret had become hostile. The one who stood up for her had become her fiercest critic and most implacable opponent.
Princess Diana At A Banquet In New Zealand | Photo: Getty Images
DIANA'S DEATH AND THE ROYAL FAMILY'S REACTION
On August 31, 1997, Diana succumbed to her injuries and was pronounced dead after a car crash. After they had informed the royal family, Prince Charles immediately wanted to take the royal aircraft to Paris to claim her body, but the Queen refused.
The press and British people accused the Queen of being unemotional or inadequately emotional in the days immediately following Diana's death. One of the tabloid headlines stated, "SHOW US YOU CARE."
Princess Diana stands with Princess Margaret and Prince Charles as they wait to meet visiting Queen Beatrix of the Netherlands in London in November 1982 | Photo: Getty Images
The Queen remained in Scotland and tried to keep William and Harry occupied. Also, the Royal Standard flag at Buckingham Palace remained absent.
However, the Queen later went on her first live broadcast in 50 years and paid tribute to Diana while defending her actions as she said they were trying to deal with the loss their way.
Princess Diana sitting on the steps outside her country home on July 18, 1986 | Photo: Getty Images
Even after Diana's untimely death, Princess Margaret would not forgive her and took the grudge to her own grave in 2002. Craig Brown, the author of "Ninety-Nine Glimpses of Princess Margaret," said,
She wouldn't even have magazines with Diana's face on the cover nearby. She would turn them over. And she wouldn't let her children talk to her.
He continually revealed that because Princess Margaret was very unforgiving, she would never have spoken to her even if Diana had lived longer.
Princess Diana aboard the new P & O cruise liner "royal Princess" on November 15, 1984 | Photo: Getty Images
When Diana's coffin passed by during her funeral, Princess Margaret gave the most cursory nods while the Queen respectfully bowed her head.
When there was an idea for a statue of Diana outside Kensington Palace, Princess Margaret scoffed at the suggestion and said she wasn't going to have "that woman" outside her bedroom window.
Princess Margaret with her son Lord Linley and his wife Lady Serena Linley leaving Westminster Abbey after the funeral service for Diana, Princess of Wales, September 6, 1997 | Photo: Getty Images
PRINCESS MARGARET'S LAST YEARS
In 1978, Princess Margaret was diagnosed with hepatitis and gastroenteritis and hospitalized for several days. In 1984, hepatitis returned, and she underwent emergency lung surgery in 1985.
In 1993, she was hospitalized with pneumonia and suffered a stroke in 1998, and in April 2001, she suffered a partial loss of her eyesight due to the effects of multiple strokes.
In February 2002, she suffered another stroke and died in her sleep on February 9, 2002, at King Edward VII Hospital.