A royal history expert told UK broadcaster ITN on Friday that Louis is a "special name" to the British royal family.
Speaking after the announcement that the infant son of the Duke and Duchess of Cambridge has been named Louis Arthur Charles, Professor Kate Williams said the decision was a tribute to Louis Mountbatten, as well as to Prince Charles and Prince Philip.
William and Catherine's third child was born on Monday, a brother to four-year-old Prince George and Princess Charlotte, who is almost three. Louis is fifth in line to the throne after his grandfather Prince Charles, his father William, and his older siblings.
The name pays tribute twice over to Prince Charles, who has Arthur as one of his middle names.
The choice also honours Mountbatten, Charles' great-uncle and beloved mentor, who was killed by an Irish Republican Army bomb in 1979.
"Louis Mountbatten… was Prince Philip's uncle and pretty much his father," said Profe Kate Williams, royal history expert at the University of Reading.
"He stood in for his father because Prince Philip was so alone when he lived in this country and also he gave a lot of support both to Prince Philip and also to Prince Charles and was lost too early due to the IRA bomb.
"So you really do see a real tribute to both Philip and Charles in this name but also to Louis Mountbatten himself who was quite a character, and he really wanted the royal family to bear his name… he wanted it to be the Mountbattens, and that was his hope.
"(Former UK Prime Minister Winston) Churchill said no, it had to be Windsor, and Louis Mountbatten and Philip were a bit upset about that - but now perhaps they've got their payday. The sixth in line to the throne is named in tribute to him."
The baby is Britain's first Prince Louis in more than a century. Mountbatten, a great-grandson of Queen Victoria, was His Serene Highness Prince Louis of Battenberg until 1917, when the royal family anglicised its names to avoid anti-German feeling during World War I. He became Lord Louis Mountbatten.
Britain has never had a King Louis, but France had 16 of them before the revolution in 1789.
Bookmakers had been doing a brisk trade in bets on the new prince's name, but Louis wasn't among the favourites. The royal couple has used it before, as one of George's middle names.
Arthur, Albert and James had been considered front-runners.