William and Catherine, the Duke and Duchess of Cambridge, have named their third child Louis Arthur Charles.

Kensington Palace said on Friday that his official title will be His Royal Highness Prince Louis of Cambridge.

Louis was a somewhat unexpected pick, but it’s clearly a name admired by the House of Windsor. It’s a middle name of the baby’s father and brother. It was also the name of the queen’s cousin Lord Louis Mountbatten, who fans of “The Crown” will know was a mentor to Prince Charles. Mountbatten was killed by an IRA bomb in 1979.

Further proving that the royals are into recycling, the youngest prince shares the middle name Arthur with his father, grandfather and great-great-grandfather, King George VI. The baby’s second middle name, Charles, is the first name of his grandfather.

Shortly after the name was announced, commentators started trying to identify hidden meanings. Were the duke and duchess paying homage to France, where the name was popular for royalty? Were they on the side of those who wanted Britain to remain in the European Union and sending a coded message about Brexit? Were they nodding to the “Suits” character Louis Litt and the growing influence of American actress Meghan Markle, soon to marry into the royal family?

“Um Prince Louis?! Really?! At a time of Brexit where we need to stand firm and support ENGLISH names like Arthur we go with a French? knew they were closet remoaners,” one Twitter user wrote in a common refrain.

Catherine, Duchess of Cambridge, leaves the hospital with her newborn on Monday. (John Stillwell/AP)

Others joked that perhaps the baby’s parents were fans of the rhythm and blues song “Louie Louie” by the Kingsmen, or the musician Louis Armstrong or, maybe, One Direction alum Louis Tomlinson.

“Even The Royal Family want a One Direction reunion,” tweeted one user.

Prince Louis was born on Monday morning.

He is fifth in line to the throne to succeed great-grandmother Queen Elizabeth II. Because of a 2013 act of Parliament, which removed preference for male heirs, he follows his sister, Princess Charlotte, in the line of succession.

William and Catherine have previously picked traditional names with historical echoes for their children. George Alexander Louis, 4, may ultimately be Britain’s seventh King George. Charlotte Elizabeth Diana, 2, was named after her grandfather Prince Charles, her great-grandmother Elizabeth and her late grandmother Diana.

So it was unsurprising that conventional names were the favorites of the bookies before the latest announcement. The favorites included Arthur, Alexander, James, Albert and Philip.

In Britain, where people can bet on nearly anything, bookmakers take in their biggest hauls for sporting events, such as soccer matches and horse races. But royal events can still attract large numbers of people placing small bets.

“The average bet for the royal baby name has been about one pound,” said Rupert Adams, a spokesman for the bookmaker William Hill. “The vast majority of people are having some fun. They are people like me: I have a son called Harry, so I put a pound on that.”

He said that betting spiked after the baby was born and that bookies take bets right up until the moment of an official announcement, unless they believe someone has inside information.

“With the date of the birth, for example, we left that up until 5:44 a.m., when somebody saw a convoy going into the hospital and called their friends and placed bets. We lost about 10,500 quid because of that,” he said.

Adams said that although on Thursday morning the odds on Louis were 3-1, the final odds were 16-1. His agency will pay out about 100,000 pounds ($138,000) to people who placed bets on Louis.

Prince Louis has been with his parents and relatives at Kensington Palace since Monday evening.

If many new parents couldn’t quite identify with Catherine’s immaculate looks when she emerged from the hospital just seven hours after giving birth, they could probably feel for William. On Thursday, he was seen nodding off during a service at Westminster Abbey.