When the Duke and Duchess of Cambridge welcomed their third child, the Queen was forced to step in to change his name.
Prince William and Kate Middleton 's youngest child was born on April 23, 2018, and the proud new parents named him Louis Arthur Charles.
Louis is a popular name in the royal family and both Prince William and Prince George have it as a middle name, in honour of Prince Charles 's mentor Lord Louis Mountbatten, who died in an IRA bombing in 1979.
The middle name Charles is a clear tribute to Louis' grandfather, the Prince of Wales.
Like his older siblings, Prince George and Princess Charlotte, Louis doesn't have a surname and is formally known as His Royal Highness Prince Louis of Cambridge.
But his HRH title was far from certain thanks to a longstanding rule put in place by King George V, reports the Express.
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In 1917, he set out guidance on which royals were allowed to have titles. It was decided then that only those closest to the top of the line of succession would be automatically granted titles.
King George V decided that only the sovereign's children would automatically become a Prince or Princess, as well as any grandchildren born through the male line.
But great-grandchildren were not included.
The Queen overturned this for Prince George, and for all of William and Kate's children.
If the Monarch didn't make the change, it's likely that Louis would have been Master Louis Cambridge or Master Louis Windsor instead.
But it doesn't extend to Prince Harry and Meghan Markle's children, which caused rows.
The subject was approached in Meghan's interview with Oprah Winfrey.
In the interview, Meghan said: "They were saying they didn't want him to be a Prince or Princess, which would be different from protocol, and that he wasn't going to receive security. This went on for the last few months of our pregnancy where I was going, hold on for a second."
"They said [he's not going to get security], because he's not going to be a Prince.
"Okay, well, he needs to be safe so we're not saying don't make him a Prince or Princess, but if you're saying the title is what's going to affect that protection, we haven't created this monster machine around us in terms of clickbait and tabloid fodder you've allowed that to happen which means our son needs to be safe."
However, experts have denied Meghan's claims that it was "different to protocol".
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