Prince William and Prince Harry's uncle has died, sending the royal family into mourning for a man who was Queen Elizabeth II's most senior aide.

Lord Robert Fellowes became Princess Diana's brother-in-law after marrying her sister Lady Jane Fellowes in 1978.

And he was Elizabeth's private secretary during some of her toughest years, from 1990 to 1999, when she endured three of her children divorcing, a fire at Windsor Castle and open warfare between King Charles III and Diana.

U.K. broadsheet The Times reported that he died of "undisclosed causes" on July 29, 2024, at the age of 82.

Prince William and Prince Harry are seen at a statue unveiling for Princess Diana where they were joined by Lady Jane Fellowes at the Sunken Garden of Kensington Palace on July 1, 2021. Center, Lord... Prince William and Prince Harry are seen at a statue unveiling for Princess Diana where they were joined by Lady Jane Fellowes at the Sunken Garden of Kensington Palace on July 1, 2021. Center, Lord Robert Fellowes' death was announced in The Times. Yui Mok - WPA Pool/Getty Images/Max Mumby/Indigo/Getty Images

Tina Brown described in her royal biography, The Palace Papers, how William and Harry would holiday with the Fellowes', while Jane played the biggest role in raising the boys among Diana's blood family.

"Their friends were the children of their father's circle," the former magazine editor wrote. "It was Diana's more sober-sided sister, don't-rock-the-boat Jane, who became a steady presence in the boys' lives, hosting them on country weekends in Norfolk with their cousins.

"Thanks to her marriage to Robert Fellowes, who stayed a lifelong loyalist to the Queen after he retired as her private secretary, she was almost a Windsor by osmosis."

So connected was Fellowes to royal life that his future boss, still Princess Elizabeth and aged five at the time, was present when he was at Sandringham, the royal family's estate in the east of England, in 1941 when he was born.

Quoted in The Times, the queen once said: "Robert is the only one of my private secretaries I have held in my arms."

Fellowes was instrumental in the pressure cooker palace crisis that unfolded in the days after Princess Diana's death in a Paris car crash at the end of August 1997.

Robert Lacey wrote in his book Battle of Brothers: "On Her Majesty's express instructions, her private secretary Robert Fellowes—Diana's brother-in-law, married to her elder sister Jane—arranged for the body to be sent discreetly to the Fulham Road mortuary used by the royal coroner.

"Charles was outraged—both on his own account and for the sake of Diana and his sons.

"He dived into a bitter slanging match with Fellowes that ended with him shouting at the private secretary, 'Why don't you just go and impale yourself on your own flagstaff?'"

The public debate quickly pivoted to why the royal family had remained at Balmoral, in Scotland, rather than returning to London where the public had been laying floral tributes to the princess.

And the queen was under pressure to fly the royal flag at Buckingham Palace at half mast, even though it traditionally only flies while the monarch is in residence.

Lacey described a phone call in which Alastair Campbell, who was spokesperson for then Prime Minister Tony Blair, attempted to persuade Fellowes that Elizabeth needed to change stance.

Fellowes replied: "I hear what you're saying. But it's a curious business, the flag at Buckingham Palace.

"There are certain things, you know, that I can deliver straight away. But I'm not sure it's going to be as easy as it looks, even if it's right, to please the public on this one."

Lord Robert Fellowes and Alexandra Fellowes attend the wedding of Prince Harry to Ms Meghan Markle at St George's Chapel, Windsor Castle on May 19, 2018. Fellowes was married to Princess Diana's sister Lady Jane... Lord Robert Fellowes and Alexandra Fellowes attend the wedding of Prince Harry to Ms Meghan Markle at St George's Chapel, Windsor Castle on May 19, 2018. Fellowes was married to Princess Diana's sister Lady Jane Fellowes. Max Mumby/Indigo/Getty Images

"Fellowes knew his boss," Lacey continued. "No flag in history had flown at halfmast over Buckingham Palace. The Queen had not done it on the death of her beloved father George VI, and she would not expect it for herself.

"It was a matter of tradition—something greater than oneself, symbolizing for Elizabeth II values approaching the sacred. It was certainly not a gesture to be conceded to the popular media."

Fellowes and the queen's press secretary Geoffrey Crawford raised the issue "with the Queen herself."

"There was clearly a need for a change of royal direction—and Elizabeth II got it immediately. Suddenly the details of what flag flew where counted for nothing."

The problem was solved when they flew the Union Jack, rather than the royal standard, at half mast in honor of Diana.

According to The Palace Papers, Fellowes was ultimately pushed out during tensions with Charles' office in the years after Diana's death.

"After 22 years of service," Brown wrote. "Fellowes had at last quit his job on the heels of a stitch- up in the Mail on Sunday.

"The paper accused him of being 'one of the prime instruments in the destruction of the monarchy's public esteem', which was hardly fair.

"He blamed the piece on [spin doctor Mark] Bolland, who shared the Prince of Wales's conviction that Fellowes was the major blockade in Buckingham Palace's acceptance of Camilla.

"The Queen showed her gratitude to her faithful private secretary by ensuring he was given a life peerage as Baron Fellowes of Shotesham in Norfolk in her Birthday Honours List of 1999."

More recently, he was a guest at Prince Harry and Meghan Markle's wedding at St George's Chapel, in Windsor Castle, on May 19, 2020.

It is entirely possible both William and Harry will be invited to the funeral, though if so there will inevitably be questions about whether both can attend given the extent of the rift between them.

Jack Royston is Newsweek's chief royal correspondent, based in London. You can find him on Twitter at @jack_royston and read his stories on Newsweek's The Royals Facebook page.

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