The birth certificate of Prince Harry and Meghan Markle’s eldest child, Prince Archie, has sparked confusion among royal watchers after one curious detail stood out.

On the six-year-old’s certificate, Harry’s full name is written as “His Royal Highness Henry Charles Albert David Duke of Sussex.” For many, the surprise came not from the long list of titles, but from seeing the name Henry rather than the familiar Harry.

Of course, this isn’t a mistake. Harry is, in fact, a nickname — and one that even British monarchs have used before. King Henry VIII, for example, was often referred to as “Harry” among friends. The Duke of Sussex himself has joked about the oddity of it all. While meeting a boy named Henry at the WellChild Awards, he explained: “My name is Henry as well. But everyone calls me Harry. I have no idea why.”

Yet, the real head-scratcher for fans wasn’t the Henry-versus-Harry puzzle. It was the absence of another title altogether. Despite being widely known as a prince, Harry’s designation on Archie’s birth certificate does not include the word Prince.

That omission struck many as unusual, particularly since Prince William’s name on the birth certificates of his three children — George, Charlotte, and Louis — does include it. His listing reads: “His Royal Highness Prince William Arthur Philip Louis Duke of Cambridge.”