Princess Anne is King Charles' secret weapon

• Princess Anne could play a key role in her brother King Charles' monarchy.
• Anne is a patron of dozens of charities and accompanied the Queen's coffin to her funeral.
• Marlene Koenig, a royal historian, described Anne as "the equivalent of the royal Energizer bunny."

Amid the swirling press, dramatic love affairs, and roiling family tensions, one royal has become a dependable presence for the monarchy: Princess Anne.

The image of the 72-year-old curtsying to the coffin of her mother, Queen Elizabeth II, after accompanying it for six hours to Edinburgh, Scotland, in September struck a chord with royal watchers around the world.

But for those who've paid attention to Anne throughout her public life, it was just the latest example of how she's held up the institution of the royal family in her own quiet way.

Anne is frequently recognized as one of the hardest-working royals in the family. The princess started in public service when she was 18 and hasn't shown any sign of slowing down since. With Prince Andrew having been stripped of his royal patronages and military titles, who better than Anne, Charles' stoic and diligent sister, to emerge as a key figure in his inner circle as his coronation on May 6 looms?

With the monarchy facing more scrutiny than ever, Charles faces an uphill battle as he seeks the approval of the British public. Though he doesn't have the ratings his mother once had, Anne could be a useful resource in Charles' effort to earn the public's favor.

Charles even introduced legislation in November to make Anne a counsellor of state, along with their youngest brother, Prince Edward. The legislation, which Parliament passed the following month, allows Anne or Edward to stand in for the king if he's ill or abroad.

Marlene Koenig, a royal historian, told Insider that the Princess Royal isn't undertaking a new challenge in this role — she's being recognized for "doing what she always does."

Anne and Charles' relationship deepened as they grew up together

Out of Elizabeth and Prince Philip's four children, Anne and Charles are closest in age. Charles, who was born in November 1948, is 21 months older than Anne. Andrew and Edward weren't born until both Charles and Anne had reached adolescence.

Koenig believes that Anne's and Charles' proximity in age allowed them to weather changes together despite the restrictions of being royal.

"Both of them grew up in the 1960s, where you had this social change within the United Kingdom, within the world, people being freer, but you still have the constraints of the monarchy," she said.

Koenig suggested that Anne didn't judge Charles for his tumultuous marriage to Princess Diana, strengthening their bond. Though Anne and Charles found partners in different ways — Anne dated Mark Phillips for five years before he became her first husband, while Charles and Diana met only 13 times before their wedding — both of their first marriages ended after reports of infidelity.

"I don't think she ever condemned him for his extramarital affairs, simply because she knew the people and she knew how miserable his marriage was," Koenig said.

The siblings moved forward with new marriages: Anne married Timothy Laurence in 1992, while Charles and Camilla, now the Queen Consort, wed in 2005. But the events of their past, combined with the deaths of both of their parents within two years, brought the royal brother and sister closer.

"She knows what he has been through," Koenig said. "And I think their relationship as two senior citizens is far better than when they were kids because they understand each other."

Anne is known as the workhorse of the royal family

She's said to be involved with more than 300 organizations, charities, and military units, and she's even started a few charities of her own. She served as the president of the Save the Children fund from 1970 to 2017 and has been a member of the International Olympic Committee since 1988.

Anne also packs her calendar with royal engagements. An analysis by The Guardian found that she carried out more than 11,000 royal engagements from 2002 to 2022, more than any other living royal. The Guardian also found that she averaged seven more appointments than Charles each year for two decades.

Buckingham Palace did not immediately respond to Insider's request for comment on the royal family's earnings. 

Koenig described Anne as "the equivalent of the royal Energizer bunny." She also said princesses like Anne and Elizabeth's sister, Princess Margaret, the Countess of Snowdon, differed from historical expectations for siblings of monarchs — before World War I, royal families often sent siblings away to be married into other royal families.

"We've never applied the term 'women's lib' to her as fighting for women's rights, but what she does is an example. You don't have to take to the streets," she said. "She's very formidable and she gets her hands dirty in terms of going into different things."

Koenig speculated it's why Charles and Camilla trusted Anne with the job of accompanying Elizabeth's coffin.

"She was the right person to do it," she said. "And she didn't hesitate: 'I'm going with my mom, I'm going to be with her to the end.'"

Anne's curtsy to her mother's coffin as it was brought into the Palace of Holyroodhouse, was a standout moment as mourners around the world looked on. It showed her admiration for Elizabeth, even after her death. 

Though the royal family's website says it doesn't have any "obligatory codes" for those who want to greet a British royal, Victoria Arbiter, a commentator and royal expert, previously told Insider that a traditional curtsy is still a sign of respect to members of an older generation.

Anne may provide counsel for Charles during his reign

Koenig said that while Anne is unlikely to receive any title changes as counsellor of state, she'll act as an advisor and confidante to her brother. She added that the princess, whom she described as self-confident, similar to Elizabeth, had proven herself to be someone Charles can lean on.

"She is very loyal to her brother and very loyal to the monarchy, and to her, serving the crown is a duty and a responsibility," she said. "And she does it without complaining."

In this way, Anne upholds the British royal family's "never complain, never explain" public-relations strategy, which was a cornerstone of Elizabeth's reign. Anne is unlike her relatives in that her personal life and opinions have rarely made the news, indicating her focus is on her work.

In October, Anne made her first trip outside the UK after the Queen's death. She rode the Staten Island Ferry in New York before visiting the National Lighthouse Museum, where she serves as an honorary chair on its expansion campaign, titled Illuminating Future Generations.

As Charles' monarchy was still getting its bearings after a monumental loss, the princess stepped into the international eye and showed that she — and, in turn, the royal family — was still moving forward.

Only time will tell if Anne's reputation helps Charles navigate a new path, but her track record shows he still has an ace up his sleeve.

This story is part of "Charles in Charge," our package of stories all about King Charles' coronation. Read the rest here.