The Duchess at 35 - ready for her second act.
She's a devoted wife and mother, but we can expect to see a more public Kate in the years to come, says Hannah Betts.
Catherine, Duchess of Cambridge - forever popularly, if anachronistically, referred to as "Kate Middleton" - turns 35 today.
As she reaches half her three score and ten, the Duchess finds herself in a seemingly happy marriage and the mother of two young children, who happen to be third and fourth in line to the throne.
She has recently been awarded honorary life membership of the Royal Photographic Society in recognition of the "talent and enthusiasm" with which she snaps images of her offspring. Moreover, the Duchess's hair and outfits always receive a good deal of attention. However, if, in her public role, she has yet to really distinguish herself, there are signs that this birthday may prove a turning point in her upping her game from fashion plate to player.
Until now there seems to have been a sense of caution about her role, leading to mutterings last month when Prince Philip, at 95, was discovered to have carried out twice as many engagements as his 34-year-old granddaughter-in-law, boasting commitments on 110 days of 2016, compared with Kate's 63.
While Time magazine may have voted her one of the world's "100 Most Influential People" in 2012 and 2013, the role of "lady-in-waiting" rather than leading lady, duchess rather than queen, dictates a certain reticence; not least where she and her husband play not second but third fiddle to the monarch, after his father, the Prince of Wales, and heir apparent. Also, unlike Diana, Princess of Wales, she must not be seen to be becoming "bigger than the show".
The Queen herself had been a decade into the job at this stage, having acceded to the throne at the age of 25. At 21 she pledged her life to country and Commonwealth, and married, having her first child a year later. Miss Middleton, at this age, was still four years from her stint at fashion chain Jigsaw. Queen Victoria, of course, was younger still when she began her 63-year reign at just 18. The start may have been a shaky one, yet, during this period, Britain amassed the largest empire history has ever witnessed.
The Queen Mother was 36 when she unexpectedly came to prominence as Queen Consort. Unprepared as she was, the former Elizabeth Bowes-Lyon became vital to the nation's morale as war unfolded, described by Hitler as "the most dangerous woman in Europe".
And even Diana - also initially celebrated as merely mother and fashion maven, seemed to have found her footing in the world by her mid-thirties. She was famed for her charity work, be it Aids, addiction, leprosy or landmines, and was at her zenith by her 35th birthday. She died at only 36.
Kate's generation is often accused of being "younger" and less independent than the preceding one. And Kate seems to be no exception. However, the legacy of Diana looms large. There is a general acknowledgment that mistakes were made; a vulnerable young woman was given insufficient support. Both her sons have made clear that their partners will not be exposed in the same way.
Indeed, some would say by keeping in the shadows and devoting herself to her family, Kate has played her role perfectly. Hugo Vickers, author of biographies of the Queen Mother and the Duchess of Windsor, says: "It's only natural that if you're in the third generation, you're going to play a supportive role. She's obviously a very important person, but you don't want to compete.
"The Queen Mother was the same when she was Duchess of York. There was Queen Mary and Queen Alexandra as well for a time, so she was rather a mousy figure for the first 13 years after she married Prince Bertie. Catherine hasn't put a foot wrong. She does her duties well, such as her involvement with the National Portrait Gallery and new role at Wimbledon.
"One thing I've been told about both Middleton sisters at Marlborough is that when they took anything on, they put their hearts and souls into it. Catherine's a supportive wife, a good daughter-in-law and a devoted mother.
"It is a story that, none the less, requires a sequel. As Kate heads towards 40, the signs are she is ready to take on new areas of responsibility. In December, the Queen stepped down from 25 of the 600 organisations for which she serves as patron. The Duchess took over the big-hitters - Barnardo's, Save the Children UK and the NSPCC.
Together with William and Harry she launched Heads Together, a mental health campaign led by the Royal Foundation in partnership with YoungMinds and seven other charities. Its aim is to end the stigma around mental illness. It is a cause the Duchess obviously feels passionate about.Look back at her legacy in 20 years' time, it is likely it will have focused on children, mental health and sport - no small concerns at a time when stress, anxiety and obesity are reaching epidemic proportions.
In the meantime, Vickers sees her as a strategic asset not to be underestimated: "She and William have brought the monarchy to a younger generation, making it more informal.
"That's the great thing about hereditary monarchy - it regenerates every time. And, right now, we've got a four-tier monarchy: the Queen and Prince Philip, Prince Charles and Camilla, Prince William and Kate, Prince George and Princess Charlotte. There's something for everyone."