They're a couple who always do the right thing, and William and Kate have done it once again. Charlotte Elizabeth Diana - it's a name that ticks every single box, including some you may not even have thought of.
The job was harder than one might think. The field of real possibles was surprisingly small, because so many of the suitable options have been taken already. Princess 'Margaret', for example, would still mean the Queen's late sister, to anyone over thirty.
Elizabeth was never really likely as a first name for much the same reason - that it's already too strongly identified with another (and rather important . . . ) member of the Royal Family. But it was always going to be in there somewhere - the Queen, and the Queen Mother apart, it's also the middle name of the Duchess herself, and of her mother Carole Elizabeth Middleton.
By the same token, 'Princess Diana' still means one person and one person only. It's a name that carries too much baggage, and difficult memories for too many. But as a middle name it's a fitting tribute - and we know how the Princes William and Harry have always made a point of honouring their mother's memory.
But 'Charlotte' has the right number of connections - with both sides of the new baby's family. Firstly, Charlotte is a diminutive of Charles (Latin: Carolus), and of course 'Carole' is the fruit of the same tree. Charlotte is also Pippa Middleton's middle name. Grandfather, grandmother, aunt - you couldn't hope to kill more birds with the same stone, could you, really?
But it's also a name with a good royal history. There was Queen Charlotte, George III's wife (the one played by Helen Mirren in The Madness of King George). There was her daughter Charlotte, who went on to be Queen of Wurttemberg in Germany. And most importantly, there was her granddaughter Princess Charlotte, George IV's only child, which gives the name a special kind of appropriateness today, when the laws of succession have just changed to allow equal rights to a female royal baby.
Two hundred years ago Princess Charlotte was the heiress of England, and when she died in childbirth in 1817, while her father and grandfather were still alive, the tragic event shook the whole country - like the death of Princess Diana, more recently. Three years ago, Diana's brother Earl Spencer christened his young daughter 'Charlotte Diana'.
Charlotte is a nice unthreatening, name, feminine but not silly. And that's yet another box ticked - how the name fits with the image of the modern monarchy. Several of those touted as possibles, like Augusta and even Victoria, might have seemed too triumphalist, too empire-building, for today Royal Family as it strives to present a picture of normality.
The little girls, as she grows, can abbreviate it to Lottie. Or else she could go for Charlie - which keeps some useful options open if she turns out a tomboy. Remember Charlie, the Revlon perfume, which was promoted as the fragrance for the trouser-wearing 'new woman' of the 1970s?
One of the questions ahead is going to be just how wide a range of options in life will be allowed to this new royal baby. So far, so good, if the choice of names is a sign. The Duke and Duchess of Cambridge are positioning their family just perfectly to face the 21st century.