When she married Prince William in the spring of 2011, Kate was seen as a dynamic young royal who was doing much to breathe new life into the sometimes-fusty House of Windsor.
But it didn't take long — beginning earlier this year — before whispered criticism of the Duchess of Cambridge began making the rounds. Some of that was just silly snipings about her wardrobe, but other remarks were of a more serious vein, touching on the role of the monarchy itself.
Now, with the birth of her first child, the 31-year-old Kate is at another crossroad in her life, facing the delicate balance between launching into parenthood and devoting time to her son, while also appearing to be a relevant and engaged royal.
"Kate's biggest challenge will be balancing motherhood with her royal duties," says Carolyn Harris, a Toronto-based royal historian and blogger.
"Certainly, if she decides to spend all her time with her child and doesn't do public engagements and charity work, there will be criticism."
But there will also likely be criticism if there's a sense the child is being raised by nannies and royal helpers, rather than mom and dad, as was more acceptable for royal children in decades past.
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"It's a very difficult line to walk," says Harris.
To date, Kate has avoided the kinds of controversy or ill-chosen adventures that have haunted other members of the House of Windsor like, for example, brother-in-law Prince Harry with his nude romps in a Las Vegas hotel room last year.
While she was the target of long-lensed photographers who found her topless on a private patio in the south of France last September, that's been the extent of her unscripted public moments.
Largely that may be because Kate's emergence as a working royal has been carefully stage-managed. While she has taken on several charities and done numerous public engagements, she has spoken little in public. Perhaps there were hints Tuesday of a growing comfort with the media, though, as she talked easily — if briefly — and more than she has in the past with reporters before she and William left the hospital with their baby.
Kate does seem to revel in the many walkabouts she's done, meeting and greeting people of all ages and backgrounds, and being warmly welcomed anywhere she goes. But overall, the result has been that there is little significant sense yet of the views or thoughts of a woman whose husband is in line to be king one day.
A lifetime job
That's not to say, of course, that she has no serious thoughts.
"I'm sure some nights when Kate Middleton goes to bed she probably has to sit back for a moment and realize who she is and where she is, and, now, what she has to do moving forward in life," says CBC royal commentator Bonnie Brownlee.
The hardest part of that is not making a mistake. "Every day you just never know what might come your way that might try to knock you down. She is on such a pedestal," says Brownlee.
"That's why they're being so careful and taking her slowly. Let her do her events, let her cut ribbons, don't talk too much yet … it's a lifetime job."
Still, while there is time for Kate to learn the ropes and no need to be in the limelight every day, Brownlee acknowledges that the young duchess's next problem will be figuring out how to have a serious royal role that is more than just being maternal.
People will say Kate looks great and the baby is cute, but the question for her becomes: "Is the stuff you're doing real, and does it make a difference and is it measureable," says Brownlee. So much more is expected of someone in that kind of royal position.
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Kate's approach to all this will likely emerge over time, and some of what she does may well be a reaction to public expectations.
"Royal mothers retreat and reappear at different times depending on how they adapt to pregnancy and motherhood," Ingrid Seward, the editor-in-chief of Majesty magazine, wrote recently in the Daily Telegraph.
Clearing the calendar
Palace officials have kept Kate's calendar clear for the rest of the year, although it's expected she will take on some engagements in the fall.
Harris looks to William's and Kate's decision earlier this year to hire a housekeeper, whose several jobs include helping with child care, as a hint toward how their public and private lives may unfold.
"That indicates William and Kate intend to be their child's primary caregivers but also to have part-time help needed for royal engagements, so clearly they're trying to balance these two aspects of their lives."
But no matter what they do, the public scrutiny will be intense.
"There's a tremendous amount of interest in the baby and, as with [Prince William's mother] Diana, this will affect how the public interacts with Kate," says Harris.
"When Diana was in Canada over Prince William's first birthday in 1983, she had the crowds asking her about William and giving her birthday gifts to pass along to him throughout the tour.
"So certainly Kate's interactions with crowds on her public engagements will reflect the intense curiosity about the royal child."
Diana also came to be known as something of a revolutionary among royal mothers.
While nannies still had a significant role in William's and Harry's upbringing, Diana also tried to ensure they had experiences outside the palace walls that would have been unknown to previous royal generations.
Part of Diana's vision was to help her young boys understand that a royal upbringing is not normal and that most people live very differently, "and I think she did that well," says Brownlee.
Kate will undoubtedly face the same challenges and objectives, while also trying to figure out her own responsibilities as a national and even international role model.
The obvious comparisons with her husband's late mother, and her tragic, outsized memory, will not make these challenges easy.