Prince Archie and Princess Lilibet: Why Meghan Markle and Prince Harry's Kids Now Have Royal Titles

Announcing Prince Archie Harrison and Princess Lilibet Diana!

For the first time, Meghan Markle and Prince Harry have referred to their children's royal titles. While confirming the news of Lilibet's recent christening, a spokesperson for the Duke and Duchess of Sussex told PEOPLE on Wednesday: "I can confirm that Princess Lilibet was christened on Friday, March 3 by the bishop in the Episcopal Diocese of Los Angeles, the Rev John Taylor."

Upon the death of Queen Elizabeth in September, Harry's father became King Charles — and as grandchildren of the monarch, 3-year-old Archie and 1-year-old Lili were afforded the titles of prince and princess. PEOPLE understands that the titles will be used in formal settings and not in everyday use.

"The children's titles have been a birthright since their grandfather became monarch," a spokesperson for the Duke and Duchess of Sussex told PEOPLE. "This matter has been settled for some time in alignment with Buckingham Palace."

The rule was established by King George V after he issued a Letters Patent in 1917 that read: "…the grandchildren of the sons of any such sovereign in the direct male line (save only the eldest living son of the eldest son of the Prince of Wales) shall have and enjoy in all occasions the style and title enjoyed by the children of dukes of these our realms."

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RICHARD POHLE/POOL/AFP via Getty Images March 11, 2019: Prince William, Prince Harry, Meghan Markle and Prince Charles chat during a Commonwealth Day appearance

Prince Archie and Princess Lilibet did not receive the titles when they were born because they were great-grandchildren of the monarch. Instead, they were styled as "Master Archie Mountbatten-Windsor" and "Miss Lilibet Mountbatten-Windsor." Their prince and princess titles are not yet reflected on the royal family's official website, but PEOPLE understands the palace will update the website to reflect the children's titles.

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However, their cousins — Prince William and Kate Middleton's three children Prince George, Princess Charlotte and Prince Louis — did get the titles as the children of the eldest son of the (now former) Prince of Wales.

When Prince Harry, 38, and Meghan, 41, were married in May 2018, Queen Elizabeth gave them the titles of Duke and Duchess of Sussex. Archie was entitled to the "courtesy title" of Earl of Dumbarton upon his birth, but the couple did not give him a courtesy title at that time. Down the line, Archie could be given the secondary Sussex title before inheriting the dukedom.

Some members of the royal family have turned down titles for their children. Queen Elizabeth's only daughter, Princess Anne, refused titles for her two children, Peter and Zara. "Zara always says she's so pleased she wasn't given a title," Phil Tindall, the father of her husband, Mike Tindall, previously told the Sunday Times, adding that the lack of a title has enabled Zara and brother "to live their own lives."

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Similarly, Prince Edward and Sophie, Countess of Wessex opted not to give their children, Lady Louise and James, Viscount Severn, prince and princess titles.

"We try to bring them up with the understanding they are very likely to have to work for a living," the Sophie told Times of London about their decision to not use "His/Her Royal Highness" titles for Louise and James. "Hence, we made the decision not to use HRH titles. They have them and can decide to use them from 18, but I think it's highly unlikely."

During Meghan and Prince Harry's March 2021 interview with Oprah Winfrey, the Duchess of Sussex said there was a conversation about titles ahead of Archie's birth.

"They were saying they didn't want him to be a prince or princess, which would be different from protocol, and that he wasn't going to receive security," Meghan said. "This went on for the last few months of our pregnancy where I was going, 'Hold on for a second.' "

Meghan went on to say she would have accepted a title for Archie if it "meant he was going to be safe."

"And it's not our decision to make," she said. "Even though I have a lot of clarity of what comes with the titles good and bad...that is their birthright to then make a choice about."

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Although Meghan and Prince Harry have largely kept their children out of the public eye, they shared several personal photos and video clips featuring Archie and Lili in their Netflix show Harry & Meghan, which premiered in December on the streaming service.