Louis, born in 1994, is the heir to Earl Spencer, Diana's brother. While her older sister Sarah McQuorquodale had George in 1984 and her middle one Jane Fellowes is the mother of Alexander born in 1983.
It wouldn't be surprising if William had been influenced by this since he has always fought to keep his mother's memory alive, most notably when he proposed to Kate with her oval sapphire.
George McQuorquodale, Louis Spencer and Earl Spencer with relatives at the royal wedding
Of course, the little Prince's name is intrinsically linked to the British royal family and has countless echoes throughout their history. King George V, the Queen's grandfather, founded the House of Windsor, of which the baby is the newest member, in 1917.
Her father, George VI, was the monarch who saw the country through its darkest hour, World War II.
Alexander is thought to be a tribute to William's grandmother, one of whose names is Alexandra and Louis is in honour of the Duke of Edinburgh's uncle, Lord Louis Mountbatten. It is also one of the names of the proud father himself.
Whatever the reasons behind their thinking, people across the country are likely to follow the royal couple's lead. Before last week George was the tenth most popular name for boys. Four days after the new heir's birth it had already climbed three places in the list of favourites.