Being a senior member of the royal family means you get all sorts of fancy titles, including HRH, dukedoms and honorary ranks.
But the Queen's relatives who are further down the line of succession don't have this privilege, which means they have to use a normal surname like the rest of us.
So while Prince George, Princess Charlotte and Prince Louis use their parents' 'Cambridge' title as their surname at school, their cousins Archie and Lilibet use the royal family's 'official' last name - Mountbatten-Windsor.
The moniker combines the royal name, Windsor, with Prince Philip's surname, Mountbatten.
However the name caused a massive row in the royal family and was even raised in the Houses of Parliament, resulting in a rift between the Queen and her husband.
It didn't appear on an official document until 1973, but the complicated story behind the name dates all the way back to 1952.
Before marrying The Queen and becoming the Duke of Edinburgh, Philip's official title was Prince Philip of Greece and Denmark of the House of Schleswig-Holstein-Sonderburg-Glücksburg.
However, his name wasn't considered to be neutral enough so he adopted the name Mountbatten after his grandparents.
When the then Princess Elizabeth had the couple's first child, Prince Charles, in 1948, he assumed, due to tradition, that their little one would take his name.
However, when Elizabeth went on to become Queen in 1952, she had to confirm the official surname of the Royal Family and many wanted her to continue using Windsor, instead of changing it to Mountbatten.
Winston Churchill is said to have been an advocate for the Royals using the name Windsor and The Queen's grandmother, Queen Mary, agreed.
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It is said to have caused such an issue that the matter was even discussed in Parliament.
In the end, the Queen decided to support her family's views and the name Windsor was used.
At the time, Philip reportedly said: "I am nothing but a bloody amoeba. I am the only man in the country not allowed to give his name to his own children."
The topic continued to bother him for years to come, but it wasn't until 1960 that Elizabeth decided to do something more about it.
When the couple fell pregnant with their third child, Elizabeth was Queen and Philip was still keen for his children to have his surname.
So in 1960, Her Majesty is said to have gone to see Harold Macmillan, who had then taken over as PM.
She said "she absolutely needed to revisit" the issue and admitted it "had been irritating her husband since 1952".
Finally, a comprise was met, and on February 8, 1960 - 11 days before Prince Andrew was born - the Queen declared that she had adopted the name Mountbatten-Windsor.
She announced that it would be used by all her descendants who do not enjoy the title of His or Her Royal Highness.
And as we have seen, it's still used today.
A statement on the Royal website explains: "The Royal Family name of Windsor was confirmed by The Queen after her accession in 1952. However, in 1960, The Queen and The Duke of Edinburgh decided that they would like their own direct descendants to be distinguished from the rest of the Royal Family (without changing the name of the Royal House), as Windsor is the surname used by all the male and unmarried female descendants of George V.
"It was therefore declared in the Privy Council that The Queen's descendants, other than those with the style of Royal Highness and the title of Prince/Princess, or female descendants who marry, would carry the name of Mountbatten-Windsor."
