The Duke and Duchess of Sussex's decision to change the way their two children were styled from Archie and Lilibet Mountbatten-Windsor to Prince Archie and Princess Lilibet caused headlines around the world. In line with the rules laid out in the 1917 Letters Patent by King George V, grandchildren of the monarch are entitled to hold princely titles - something which Prince Harry and Meghan referenced in their statement at the time as they said they didn't want to deprive their children of their "birth right".