It’s way simpler than you think.

Arrizabalaga/Epa/REX/Shutterstock

When Prince George started school this year, many asked a crucial—yet uncommon—question: What will his classmates and teachers use when referring to his last name? (Here’s what they decided on, by the way.)

It’s a well-known fact that the British royal family doesn’t have a last name. But why? The reason is simple: They don’t need one. “They’re so famous that they’re easily identifiable without one,” Business Insider reports.

Fair enough. However, the history behind the British royal surname is a bit more complicated than that. Historically, royal family members haven’t had a last name at all; they only answered to their first names and the house or dynasty they were members of, such as House of Tudor or House of York.

Then, in 1917, King George V designated “Windsor” as the royal family’s official surname—a nod to the Windsor Castle, one of the royal properties. To this day, the British royal family is still known as the House of Windsor. That’s the last name that Queen Elizabeth II goes by, too. When she married Prince Philip, however, they decided that their offspring would take the hyphenated last name Mountbatten-Windsor.

Here’s where things get tricky, though: No one is obligated to carry the Mountbatten-Windsor name. Though there are rules the royal family absolutely must follow, this isn’t one of them. Instead, any royal with the title “His Royal Highness Prince” or “Her Royal Highness Princess” may use a surname of their choosing. That’s why some members of the royal clan have adopted their family’s territorial designation, including Prince William and Prince Harry, who went by William Wales and Harry Wales while in serving in the military because their father is the Prince of Wales. (To make things even more complicated, Prince Harry’s real name isn’t actually Harry.)

As for us? We’ll stick to referring to the royal family on a first name basis. If you’re confused as to who’s who, this chart explains the entire royal family tree.

[Source: Business Insider]