Baby Lilibet and Archie Will Inherit 'Princess' and 'Prince' Titles When Charles Becomes King
Under current guidelines, great-grandchildren of the monarch are not princes or princesses
The couple are parents to 2-year-old son Archie Harrison and their newborn daughter Lilibet Diana, who they welcomed on June 4. When the siblings' grandfather Prince Charles steps into the role of monarch upon the death of Queen Elizabeth, the two children will likely become a prince and princess.
Under current guidelines, great-grandchildren of the monarch are not princes or princesses, except for children of the eldest son of the Prince of Wales, which is why Prince William and Kate Middleton's children are Prince George, Princess Charlotte and Prince Louis.
But when Prince Charles becomes king, automatically the title of "prince" will be given to Archie and the title of "princess" will be given to Lili as the children of a son of the king.
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."
"As the grandchildren of the Sovereign, they have the right to be upgraded to the style of His or Her Royal Highness. But that begs a question of whether Harry and Meghan want that," Joe Little, managing editor of Majesty magazine, previously told PEOPLE.
Little continued: "Do they prefer what [Prince] Edward and Sophie have, and not have their children as Their Royal Highnesses with a view to them leading relatively normal lives?"
When Prince Harry, 36, and Meghan, 39, were married in May 2018, the Queen gave them the titles of Duke and Duchess of Sussex. Archie was entitled to the "courtesy title" of Earl of Dumbarton upon his birth. However, the couple announced that they had not given him a courtesy title and he would be known as Archie Mountbatten-Windsor. Down the line, Archie could be given the secondary Sussex title, before inheriting the dukedom.
During Meghan and Prince Harry's interview with Oprah Winfrey, which aired in March, the Duchess of Sussex revealed 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."
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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."