Ahead of the birth of Prince William and Kate's first child in 2013, the late monarch issued a formal decree to ensure that if the baby was a girl, she would be given the title of Princess.
Up until that point, the Letters Patent 1971 stated that only the eldest son of the eldest son of the Prince of Wales was entitled to be made Prince.
Using a new Letters Patent, the late Queen decided that all of William and Kate's children would be given the title of Prince or Princess.
A formal announcement in the London Gazette at the time read: "The Queen has been pleased by Letters Patent under the Great Seal of the Realm dated 31 December 2012 to declare that all the children of the eldest son of The Prince of Wales should have and enjoy the style, title and attribute of Royal Highness with the titular dignity of Prince or Princess prefixed to their Christian names or with such other titles of honour.",
William and Kate welcomed Prince George on 22 July 2013, but if the change still hadn’t been made by the late Queen at the time, Princess Charlotte and Prince Louis would have been known as Lady and Lord, as only their eldest son would have been given the title of Prince.
Charlotte also made history at the age of two as she was the first female royal to benefit from The Succession to the Crown Act (2013), which states that girls will not be overtaken by any future younger brothers.
She kept her place in the line of succession above her younger brother Prince Louis, when he was born in April 2018.
Following the death of Queen Elizabeth II on 8 September 2022, William and Kate became the Prince and Princess of Wales.
They were formerly known as the Duke and Duchess of Cambridge – titles which were given to them on their wedding day in April 2011 by the late Queen.
What other titles could George, Charlotte and Louis hold in future?
When William becomes King, George could become the Prince of Wales, but this title is neither automatic nor heritable.
George, who is second-in-line to the throne, is also expected to one day be King.
Charlotte could be given the title of Princess Royal in future, but only if it isn't being in use by someone else. Princess Anne is the current Princess Royal.
George, Charlotte and Louis could all be given different titles on their wedding days, as traditionally has happened.