Although, Prince William and Prince Harry are brothers, their children do not share the same surname.
Prince William and Kate’s three children, Prince George, Princess Charlotte, and Prince Louis have the last name Cambridge, taking after their parents’ royal titles as the Duke and Duchess of Cambridge.
Two days after Meghan gave birth to Archie, the palace announced his name without an affixed title, indicating that the Duke and Duchess wish for him to have a more normal and private life. Instead, Archie Harrison carries the royal family’s last name—Mountbatten-Windsor.
The family name stems from Prince Phillip’s surname, which is Mountbatten, and the name Queen Elizabeth II’s grandfather, King George V, took on, Windsor, after Windsor Castle in 1917.
Members of the royal family don’t normally use their surnames. They are known by their first name or title in the public eye. According to the royal family’s official website, a declaration made by the Queen in Privy Council in 1960, said that male-line descendants of the monarch, without royal styles and titles, shall bear the name Mountbatten-Windsor.
The website adds: “Unless The Prince of Wales chooses to alter the present decisions when he becomes king, he will continue to be of the House of Windsor and his grandchildren will use the surname Mountbatten-Windsor.”
When Prince William and Prince Harry started school, their parents decided they wanted their children to live a more normal life, so they decided to give their children the surname ‘Wales’ so they could fit in. The surname ‘Wales’ comes from their father, Prince Charles’ title- Prince of Wales.
But, after they got married, William and Harry were granted new titles from their grandmother the Queen, and their children are expected to take these on.
In a similar vein, Princess Eugenie and Princess Beatrice also use the surname ‘York’ after their father Prince Andrew, the Duke of York.