One of the more noteworthy quirks of the British Royal Family is that its members are usually referred to with just a title and a first name. Queen Elizabeth II, Prince Charles and others are not typically given a last name in the media.

That said, there is technically a last name that male descendants of the Queen, including Prince Harry, can use whenever it is needed. The Duke of Sussex and several other men in the Royal Family officially use the surname Mountbatten-Windsor, according to the Royal Family website.

That means Prince Harry’s full name, on occasions that call for it, might be Prince Henry Charles Albert David Mountbatten-Windsor of Wales. Given the circumstances, it is understandable why royals might elect not to use their full names.

Prince Harry, Duke of Sussex, Captain General Royal Marines, visits 42 Commando Royal Marines at their base in Bickleigh to carry out a Green Beret presentation at Dartmoor National Park on February 20, 2019 in Plymouth, England. Finnbarr Webster/Getty Images

Where does Mountbatten-Windsor come from, and why do male royals typically not use it? Its history is somewhat complex, according to the family’s website. Before 1917, the Royal Family did not have an official last name; instead they used their house name to distinguish themselves.

The dynasty was named the House of Saxe-Coburg-Gotha until World War I. Anti-German sentiment in the United Kingdom at the time prompted then-King George V to change it to Windsor, proclaiming that to be the Royal Family’s official surname.

The Queen took it one step further in 1960 by declaring that all of her male and unmarried female descendants would go by Mountbatten-Windsor. It is a hyphenation of her own family’s last name and that of her husband Prince Philip, who took the Mountbatten name when he became a naturalized British subject.

Interestingly, the Royal Family website also says the current King or Queen’s declaration of a last name is “not statutory.”

“Such a proclamation is not binding on succeeding reigning sovereigns, nor does it set a precedent which must be followed by reigning sovereigns who come after,” the website reads.