Britain's Prince William and his wife Kate have named their baby son Louis, royal officials said Friday, prompting online comments on popular culture references and even an anti-Brexit message in the unusual moniker.
"The Duke and Duchess of Cambridge are delighted to announce that they have named their son Louis Arthur Charles," said a statement from Kensington Palace, the couple's London residence.
"The baby will be known as His Royal Highness Prince Louis of Cambridge," it said.
The name likely pays tribute to William's great-great uncle Louis Mountbatten, who was killed by the IRA in 1979, while Charles is the name of William's father.
But the Daily Mail tabloid pointed out it was also a favourite for French kings and had "a distinctly Gallic royal flavour".
"In a defiant two fingers to Brexit, William & Kate have given their baby a French name: Louis," TV presenter Piers Morgan wrote on Twitter.
The French embassy to London tweeted: "We're delighted that you've been given such a lovely French name!"
Louis is currently only the 71st most popular name for a baby boy in England and Wales.
Other commentators joked the royal couple may have been inspired in their choice after meeting One Direction star Louis Tomlinson.
Pottermore, author JK Rowling's publishing company, instead pointed out that Louis, Arthur and Charles were all members of the Weasley family from the bestselling Harry Potter books.
"You were named afer three iconic Weasleys," it said.
Arthur had been the bookmakers' favourite for the couple's third child, while Charles is the name of William's father.
The baby was born weighing eight pounds and seven ounces (3.8 kilogrammes) at 11:01 am (1001 GMT) on Monday with William, the Duke of Cambridge, present for the birth.
The couple stepped out of St Mary's Hospital in central London to cheers from a crowd of supporters and global media outlets gathered outside.
Their two other children -- Prince George, aged four, and two-year-old Princess Charlotte -- were also taken to meet the latest addition to the family.
Louis is fifth in line to the throne and a sixth great-grandchild for Queen Elizabeth, who turned 92 on Saturday, and her husband Prince Philip.
He will hold the title of prince after the Queen changed the rules in 2012 to ensure that all of William's children would be entitled to the style, not just his eldest son.
Prince Louis is also the first male royal who will not overtake his sister in the line of succession after a reform that ends male primogeniture.
Louis Mountbatten was the beloved great-uncle of Prince Charles, and the uncle of the Duke of Edinburgh.
Known to Charles as "Uncle Dickie", Mountbatten was the last British Viceroy of India before independence in 1947.
He was assassinated by Irish republicans when his boat was blown up on a fishing trip off the coast of County Sligo in the Republic of Ireland.
Louis is also a middle name of Prince George.
William, who is destined to become king after Charles, met Kate at St Andrew's University in Scotland.
They tied the knot at Westminster Abbey in London on April 29, 2011, in a ceremony watched by up to two billion people worldwide, helping to breathe new life into Britain's monarchy after years of crisis.
The birth kicks off a busy summer of royal celebrations, with Prince Harry set to marry his US actress wife Meghan Markle on May 19.
The Sun newspaper has reported that Kate's sister Pippa Middleton, 34, is pregnant with her first child, while William's cousin Zara is set to give birth towards the end of the summer.