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In his inaugural address as King on Sept. 9, Charles, 73, thanked supporters for their condolences and spoke lovingly of both his mother and his father, Prince Philip, who died at age 99 just 17 months before his wife of 73 years.

“To my darling mama, as you begin your last great journey to join my dear late papa,” the new sovereign said, in a speech broadcast around the world, “I simply want to say this: Thank you.”

As the first chants of “God Save the King” began to rise over the U.K., admirers flooded the gates of Buckingham Palace to memorialize a woman who, for many, represented a model of duty.

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She was not without her critics, who pointed to the royal family’s colonial past and staggering privilege, both of which the Queen was reluctant to address. But no one disputes her role as a constant in an ever-changing world, who, when thrust into service as a young wife and mother at age 25, did not blink.

“She will be missed by so many,” Princess Catherine, as she is now formally known, told the crowd in an appearance with William, Prince Harry and Meghan Markle outside Windsor Castle on Sept. 10 — a surprise show of unity that reflected the brothers’ shared affection for their grandmother.

“It’s lovely to see the outpouring of love from people of all ages here today. It’s hugely touching to see,” the princess added.

In the enduring irony of her life, the woman who ruled as Britain’s longest-reigning monarch was never supposed to be Queen.

In 1936, her uncle Edward VIII abdicated to marry twice-divorced American socialite Wallis Simpson, making her father King George VI and Elizabeth next in line.

Aware of her destiny, young “Lilibet” would prove herself a natural leader with a precocious calm that would become her hallmark. In 1940, at age 14, she gave her first radio address, speaking to thousands of children who had been separated from their parents during the Blitz — just as she and her sister Princess Margaret, then 10, had been sent away to Windsor while their parents remained in London, a signal of national strength and solidarity.

“We know, every one of us,” Elizabeth reassured her listeners, “that in the end, all will be well.”

As a young woman, she fell in love and wed Prince Philip of Greece, a dashing Royal Navy cadet five years her senior, in 1947. They went on to welcome their first son Charles in 1948, and daughter Princess Anne in 1950, and were abroad in Kenya two years later when everything changed.

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On Feb. 6, 1952, King George VI died of lung cancer at age 56, making Elizabeth Queen.

“It was a terrible moment—she was very close to the King,” her lady-in-waiting Pamela Hicks later recalled. Yet when Martin Charteris, her private secretary, found Elizabeth in the lodge, she was “sitting erect, no tears, color up a little, fully accepting her destiny.”

When she was crowned on June 2, 1953, half a million subjects lined the streets to glimpse their young Queen as she rode through London in a stagecoach.

Below the shimmering surface, she faced a daunting job: leading her nation in an era when few women did so, balancing work and family before the term “working mom” was in the public discourse. A few years later, the royal family would expand when the Queen gave birth to Prince Andrew in 1960 and Prince Edward in 1964.

“My grandmother becoming Queen at a very young age, in the days when it was a man’s world, it was very difficult for her to make a difference,” William said in a 2019 interview. “And she’s done it.”

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Resolutely neutral on political matters with a knack for connecting with others while giving very little of herself away, “she had a great curiosity about people and was a great judge of character,” says Samantha Cohen, her former assistant private secretary. “She was interested in people. That was the great unifying force. With all these prime ministers and leaders, she was able to relate to them as people. Male leadership is often transactional, and female leadership is relational. She built relationships with people like [Nelson] Mandela and [Ronald] Reagan, and those relationships endured.”

Resolute in her routine, she rose every morning at 7:30 to BBC’s Today program on her Roberts Radio, enjoying Twinings English Breakfast tea and a Marie biscuit. Until she died, she worked through her famous “red box” of official papers each morning, carefully studying them and the ways in which the monarchy connected with the public. (Just as she ushered in the television era with her coronation, she later embraced social media, including Instagram and Twitter.)

Although renowned for her stiff upper lip, “Grannie” (as she was known affectionately to her eight grandchildren and 12 great-grandchildren in the last act of her long life) preferred “the countryside rather than the city, small rather than large, private rather than crowded, animals rather than humans,” says Peter Morgan, the creator of The Crown and the Oscar-winning 2006 film The Queen, both of which explored her hidden world.

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In a relatable refuge, she leaned on her pets during times of personal crisis.

In 1992 she weathered her “annus horribilis,” marked by a fire at Windsor Castle and scandal surrounding the marriages of her sons Charles and Andrew. When Charles’s ex-wife Diana, whose popularity had captivated the world, was killed in a Paris car crash in 1997, the Queen was criticized for being slow to acknowledge the public’s grief. Privately, however, she was an essential support to her devastated grandsons William and Harry.

“She was by my side at my happiest moments,” William said in a statement on Sept. 10. “And she was by my side during the saddest days of my life.”

Camilla, Queen Elizabeth, Meghan Markle, Prince Harry and Prince William. CHRIS JACKSON/CHRIS JACKSON/GETTY

Her bond with Harry remained strong even after he and wife Meghan made the decision to step back from royal life in 2020 — an arrangement that the Queen herself helped negotiate during the infamous “Sandringham Summit” alongside William and Charles.

Thrilled to have the whole family come together for her Platinum Jubilee in June, a royal source says she simply wanted to see her loved ones content.

“She had seen everything and probably thought of what happened to her own uncle. She knew that conflicts were a part of life, and she didn’t hold grudges,” they explain. “Most of all, she wanted to see her family happy and her children happy.”