Prince William and Kate Middleton may not be the only ones in the royal family inheriting new titles following the death of Queen Elizabeth II. Though Prince Harry and Meghan Markle gave up their respective His and Her Highness titles when they stepped back from their royal duties in 2020, their children-3-year-old son Archie Harrison and 15-month-old Lilibet Diana-are officially entitled to be called prince and princess now that their grandfather, King Charles III, ascended the throne as the Queen’s heir and their father moved up in the line of succession. Guidelines set forth by Harry’s great-great-grandfather King George V back in 1917 permitted royal titles to be given to children of the sovereign’s sons (a.k.a. their grandchildren descended from males). When the Queen was in power, Harry’s children were her great-grandchildren. Now that King Charles has taken the throne, Harry’s kids are officially grandchildren to the monarch and therefore qualify. The 1917 rule additionally reserved royal titles to children of the sovereign and the eldest son of the sovereign’s eldest son What about Princess Charlotte and Prince Louis? All of William’s children have actually had their titles all along, because of a new guideline passed 10 years ago.