Catherine Elizabeth Middleton became the Duchess of Cambridge on April 29, 2011, when she married Prince William, who that day got the title of Duke of Cambridge.
The Queen also conferred two other titles on the couple shortly before the wedding ceremony: William, who is second in line for the throne, became Earl of Strathearn and Baron Carrickfergus, making Middleton the Countess of Strathearn and Baroness Carrickfergus.
The two married in a late-morning ceremony at Westminster Abbey. Middleton wore a white and ivory, V-neck, long-sleeved gown handmade with satin gazar and French Chantilly and English Cluny lace. The gown was designed by Sarah Burton of the British Alexander McQueen fashion house, a detail that had been a heavily guarded secret up until the moment Middleton stepped out of the Rolls Royce that took her to the Abbey.
A long courtship
William, 28, and Kate, 29, announced their engagement in November 2010.
"It was a total shock and very exciting," was how Middleton described the marriage proposal at the time.
In fact, the engagement itself had actually happened three weeks earlier in Kenya.
By then, the couple had been in an on again, off again relationship for nine years — the last six of them in the media spotlight.
"Waity Katie," as she was called by some British media, may have wanted the proposal to come sooner but should not have been surprised that William popped the question when he did given that he had said publicly in 2004: "I don't want to get married until I'm at least 28 or maybe 30."
What only the couple knew was that they had made a secret pact to marry in August 2007 while on a trip to the Seychelles, according to Katie Nicholl, author of The Making of a Royal Romance.
Middleton was born Jan. 9, 1982, six months before her future fiancé. She was raised in the small village of Bucklebury in Berkshire, about 90 kilometres west of London.
Her father, Michael, was a flight dispatcher who came from a line of wealthy wool merchants.
Her mother, Carole, was an airline hostess for British Airways with working class roots, including a great-grandfather who'd been a coal miner. Through Michael Middleton's family, Kate and William are 17th cousins.
The Middletons had been married for two years when they had their first child, Kate. When she was five, they started their own company, Party Pieces, a mail-order business selling party supplies that they still operate out of Reading, U.K.
Party Pieces became quite successful, with 30 people now working there. Kate left the family business in January.
During her secondary school years, Kate attended exclusive Marlborough College in southwest England. Classmate Charlie Leslie told the BBC in 2005 that "Kate is an absolutely phenomenal girl — really popular, talented, creative and sporty."
The BBC also quoted a college master saying "I don't think you'd find anyone in Marlborough with a bad word to say about her. She excelled in all her subjects and was an A-grade pupil across the board."
Kate's friend Jessica Hay told News of the World in 2004 that Kate would 'moon' the boys' boarding houses from her dorm window at Marlborough.
In 2001 Kate — and William — headed to the University of St. Andrews in Fife, Scotland. Kate and William were in the same art history class.
By the end of freshman week Kate had been voted the prettiest girl in St. Salvator's, the residence hall where both Kate and William had rooms. Soon they would be eating a breakfast of muesli and fruit at the same dining table.
Kate's Canadian connection
Kate's grandfather, Peter Middleton, visited Canada when he was 17, arriving with a group of students for a "School Empire Tour Party" in August 1939, according to genealogy site Ancestry.ca. His name is on a passenger list showing he arrived in Quebec from Liverpool on Aug. 11, 1939, on the SS Andania.
He was also stationed in Calgary during the Second World War while training with the Royal Air Force. He was posted to Canada as a flying instructor for two years before returning to Britain to join 605 Squadron at Manston, Kent, in August 1944.
It was Peter Middleton’s death in November 2010 that delayed the announcement of William and Kate's engagement.
In March, 2002 Kate volunteered as a model in a charity fashion show. She wore a black see-through dress that caught the eye of a student seated in the front row: Prince William.
"Kate was great on the catwalk," Nicholl quotes one of the other models as saying. "She and everyone, including William, knew it."
It was at the after-party that William made his move, according to Nicholl, even though Kate was then dating Rupert Finch, another student, who years later would be invited to Kate and William's wedding.
At the start of second year, Kate, William and two other students shared a townhouse in Fife. Kate and William had bedrooms on separate landings, a pretense so they could keep their fledgling romance quiet.
Jules Knight of the classical vocal quartet Blake was in that same first year art history class. He quickly became friends with both Kate and William.
"They spent a lot of time together and were very good friends for a long time and then that blossomed into something more. And it's not surprising, really, because Kate's a fantastic girl," Knight told the BBC.
Two years in, the romance hit the front pages of the Sun newspaper on April 1, 2004, with a fresh photograph and the headline, "Finally, Wills gets a girl." The photo showed them together at a Swiss ski resort.
Breakups in 2004 and 2007
That summer, the couple began a trial separation but were back together by Christmas.
In June 2005, with the Queen attending, Kate graduated from St. Andrews, as did William.
The couple spent a good part of the summer of 2005 together at the Lewa Wildlife Conservancy. That's where, five years later, William would give Kate the blue sapphire engagement ring that had belonged to his late mother, Diana, Princess of Wales.
In 2006, Kate went to work as an accessory buyer at the fashion chain Jigsaw, which is owned by family friends of the Middletons.
In 2007, Kate and William had another break-up, reportedly over William's lack of full commitment to their relationship.
But they were soon back together.
"At the time, I wasn't very happy about it, but actually, it made me a stronger person," Kate said in the couple's first interview after the engagement was announced.
About their time apart she added: "I really valued that time for me, although I didn't think it at the time."
In September 2008, William announced he wanted to become a Royal Air Force search-and-rescue-pilot, news that took everyone, including Kate, by surprise. For William, it meant he would be able to continue to live a "normal" life for a few more years. But for Kate, it meant she would be an army girlfriend and that any wedding date would be further off.
In early 2010, William transferred to an RAF training base on the Isle of Anglesey, Wales, where the couple have been living for over a year.
'Kate from Party Pieces'
In March 2010, the Party Pieces blog featured an interview with "Kate from Party Pieces." It is believed to be Kate's only interview until the day the engagement was announced.
She talked about her own party memories growing up. Her best memory was an "amazing white-rabbit marshmallow cake that Mummy made when I was seven," and her worst was "being very upset that the pink fluffy shoes I won in 'pass the parcel' didn't fit."
Some commentators especially liked one of the bits of party advice she offered, interpreting it as something Prince Harry, her future brother-in-law, ought to have benefited from: "If you are having a dressing-up party, try and find yourself a suitable costume. Don't make it too scary or weird as children might not want to stay." Five years earlier, Harry had attended a costume party in a Nazi uniform.
After being on the Party Pieces website for about five days, the interview disappeared.
Kate's sister, Pippa, 27, also works at Party Pieces. Her brother, James, 23, now has his own business, The Cake Kit Company. Like Kate, both attended Marlborough College. Pippa and James then attended University of Edinburgh.
Pippa is a favorite of the U.K. tabloids, not only because she was often at Kate's side in public, but because of the men she dated: an heir to a Hong Kong banking dynasty, a diamond heir, a Scottish aristocrat and two sons of dukes.
In 2007, the Daily Mail reported, "Kate and Pippa have already been dubbed the Wisteria Sisters — they're highly decorative, terribly fragrant and have a ferocious ability to climb."
William and Kate plan to tour Canada in July.