Prince William and Kate Middleton may still be decades away from becoming king and queen, but when the time comes, they'll be ready.

And those who enjoy having a monarchy in their midst can rest assured that William has picked just the right person to be by his side for the duration of the journey, much as Queen Elizabeth II did 75 years ago. "I think that Kate is a bit like Prince Philip supporting the Queen," royal biographer Penny Junor told People in 2020. "She doesn't outshine William but still has a lot to say herself."

It was no secret that Kate, the new Princess of Wales, had been steadfastly stepping up as William took on more responsibility as time marched on—the concept never more stark than when his father became King Charles III last September upon the death of the queen. She had spent a record 70 years on the throne, a reign that isn't likely to be surpassed. 

Celebrating their 12th wedding anniversary April 29, Kate and William may be ye olde married couple, but even as blushing newlyweds they were expected to be elegant, magnanimous and endlessly stoic. Their three children—Prince George, 9, Princess Charlotte, 7, and Prince Louis, 5—all bear a series of names signaling their rich heritage. They've had to carefully toe the modern-but-traditional line, coming across as more relatable than their predecessors but by no means normal. 

All of which we now accept as a given. But the still-young royals haven't always been the picture of propriety.

Once upon a time, Kate was a college student catching her 19-year-old pal William's eye as he glimpsed her undies under a sheer black slip of a dress at a student fashion show.  "Kate's hot!" was William's storied reaction, as whispered to his best friend Fergus Boyd.

Kate is the daughter of a couple of commoner millionaires, Carole and Michael Middleton, whose fortune came from the online party-planning business, Party Pieces, that they started in 1987. Kate is the eldest of three, sister Pippa and brother James rounding out the family fold in the Berkshire village of Bucklebury.

She was an athlete, like William. A worldly art appreciator, like William. And, starting their second year at University of St. Andrews, they were both residents of the same flat on one of the nicest streets in the neighborhood, which they shared with Fergus and another friend, Olivia Bleasdale.

But they were just a couple of mates rooming together, as far as the official word went at the time.

William's angelic face, big blue eyes and thick head of sandy-colored hair launched "Willsmania!" all over the U.K. when he was barely 14. His mother Princess Diana invited supermodels Naomi Campbell, Cindy Crawford and Christy Turlington to Kensington Palace to meet him as a surprise, because he had their posters on his wall.

By the time William went to college, he hadn't had any long-term girlfriends, but he was rarely alone. He usually operated in groups that included young ladies, such as when he entertained five aboard a yacht cruising the Greek islands when he was 17. (However, one girl was his cousin, another his future stepsister, and his dad and future stepmother, now-Queen Camilla, were also aboard.)

Pals included Holly Branson, daughter of billionaire business mogul Richard Branson, and Violet von Westenholz, who down the road would set Prince Harry up on a blind date with Meghan Markle.

The summer after he finished Eton, William is said to have grown close to childhood friend Rose Farquhar. 

"She still refers to him as her first true love," a friend from their "Glosse Posse"—the privileged young people who constituted William and Harry's inner circle from time spent at their dad's estate, Highgrove, in Gloucestershire—recalled to Katie Nicholl for her 2011 book The Making of a Royal Romance. "That summer they realized that they both actually rather liked each other and it was William who made the first move."

"It was a very sweet and innocent love affair and Rose still laughs about the time they got caught by a farmer in a field. They are still good friends."

Inquiring minds were dying to know, but as 18-year-old William said on the occasion of his milestone birthday in June 2000 (he didn't sit down for a formal interview but agreed to answer questions from a select group of media), "I like to keep my private life private."

Asked how he managed to have a private life amid all the attention he received, particularly from young ladies, he offered, "In my own way. Trying to explain might be counterproductive."

William took off for Santiago, Chile, on Oct.1, 2000, to kick off his gap year; Kate also took a gap year to travel after graduating from Marlborough College, and she too touched down in Chile at one point.

Though Kate was certainly aware of William's existence long before they crossed paths, they eventually met in the dorm at St. Andrews during their first year of university.

Kate had been crowned the prettiest girl in their residence hall. William eventually invited her to join his regular breakfast table and they became fast friends, bonding over their shared interests in sports and ski trips and art history. They went for morning swims and took strolls through town, and Kate got along with William's pack of friends. She was an obliging ear when he struggled with art history and decided to switch his concentration to geography.

But still...just mates.

The prince, who was rather interested in acting, started dating a creative writing student named Carly Massy-Birch, whom he met in drama club.

"She was quite a catch and every girl at St. Andrews was envious of her because she was with William," a friend of Carly's told Nicholl. Their relationship apparently ended when Carly told William to choose between her and—no, not his close pal Kate—but Arabella Musgrave, another girl he'd known since childhood whom he had run into at a party in the summer of 2001.

Then-Prince Charles, knowing all too well the importance of being free to live one's life (within reason, of course), instructed his son's protection detail to let William for the most part do as he pleased. Arabella's father, however, told the kids to quit it with the PDA when he spotted them canoodling at a polo match.

They had mutually agreed to break off their relationship when William left for St. Andrews, but he was homesick for awhile.

But, keeping in line with his pattern of having girls as friends and then all of a sudden realizing one day that they had turned into swans, it was the fashion show, in March 2002, that made William see Kate as more than just a friend.

Kate, meanwhile, had been dating fourth-year student Rupert Finch, but Will swooped right in at the after-party.

"It was clear to us that William was smitten with Kate," a friend who witnessed the moment (which included an awkward attempt at a kiss that visibly startled Kate) recalled to Nicholl. "He actually told her that she was a knockout that night, which caused her to blush."

But Kate, not wanting to buckle just because the prince was all of a sudden interested, "played it cool," the friend added. "She didn't want to give off the wrong impression or make it too easy for Will."

She also didn't immediately break it off with Finch, but by the end of their first year at St. Andrews, Kate and William were obviously into each other. And then they decided to live together—with other people, but still an arrangement fraught with potential.

Whatever their differences, Charles and Diana had been in agreement about wanting William and Harry to live full, as close to normal lives as possible. A protection officer always occupied a nearby room when the boys were at school, but William's private co-ed living arrangement during his second year was something new. In fact, William had insisted on being allowed to live off-campus his second year as a term of his return to school after a shaky first semester.

While Tim Graham and Peter Archer were writing the 2003 biography William, they included that friends were saying that Will and Kate were not romantically involved. And William himself declared during an interview coinciding with his 21st birthday that June that he was single.

"If I fancy a girl and she fancies me back, which is rare, I ask her out," he explained. "But at the same time I don't want to put them in an awkward situation, because a lot of people don't understand what comes with knowing me, for one—and secondly, if they were my girlfriend, the excitement it would probably cause."

But they were taking their chances.

Per Nicholl, a 2002 game of "I've Never" turned awkward when William, Kate and Carly—who ended up living across the road from them—all ended up at a dinner party and Carly offered, "I've never dated two people in this room," knowing that Will was by then dating Kate and, if he was being truthful, would have to take a shot—signaling that he had dated two people in the room.

Kate, already not a big fan, was done with Carly after that.

So, the locals knew, but William and Kate were still playing it ultra-cool, never arriving at a party or dinner together or leaving at the same time, let alone hand-in-hand, and not protesting too much if William was photographed with another girl and subsequently ended up linked to her.

Kate's parents waited until June 2003, when the school year was over, to throw her a 21st birthday party (her birthday's in January), and William certainly didn't seem like just a friend.

Not being in on the secret, however, Kate's dad, Michael, told a reporter that he doubted that he and his wife would end up with royal in-laws.

And according to Nicholl, William seemed to be paying special attention at his 21st birthday party at Windsor Castle later that month to Jecca Craig, whom he had met in Kenya while on vacation in 1998.

Right in front of Kate.

But William always insisted he and Jecca were just friends—and she was dating a friend of his. (William attended her wedding in Africa in 2016.)

"There's been a lot of speculation about every single girl I'm with, and it actually does quite irritate me after awhile, more so because it's a complete pain for the girls," he said in a rare refutation of a story about his private life after one report had he and Jecca pledging their love to each other in a mock ceremony.

But as Kate and William began year three at St. Andrews in September 2003, they were less cautious about being a couple out in the open. They lessened their roommate count to one (not including security), moving into a four-bedroom cottage on the grounds of Balgrove House with their friend Oli Baker.

The cat was forever let out of the bag when Will was photographed with his arm around Kate atop a mountain in the Swiss village of Klosters, a favorite royal family skiing spot, and The Sun was all too happy to share the news that Prince William had a girlfriend.

The palace was pretty ticked off, as the media had been observing a light-touch approach to covering William and Harry while they were in school, but the tabloid had the scoop of the year.

After that, the press were all over Kate, who comported herself admirably amid the excitement that, as predicted, William dating someone did indeed cause. Moreover, her family didn't talk to the press, and William loved spending cozy weekends at the Middleton homestead.

Kate, in turn, enjoyed spending time at all of the various family homesteads William brought her to, where on any given weekend there could be a hunting party or other event at Highgrove, Windsor, Sandringham or Balmoral. 

The queen, in fact, had given William a key to Tam-na-Ghar, a cottage at Balmoral, to unwind on weekends, and it became a regular getaway spot for him and Kate, sometimes alone, sometimes with a group that at times included Kate's brother and sister.

But when their third year at St. Andrews ended, in 2004, William planned a sailing trip to the Greek islands that did not include Kate—but for which his good pal Guy Pelly had arranged an all-female crew. 

Pelly is now one of Prince Louis' godparents, but back then Kate may have been a touch annoyed at him.

Not convinced that William was ever going to commit fully, and with the names of all sorts of female-socialite friends of William's running through her head, Kate went home to her family for the summer. She spent two weeks in France, where Fergus Boyd had invited a group of college friends to his family's place in Dordogne—and one night, fueled by wine, she admitted how much she missed William.

Otherwise, she tried to keep a stiff upper lip.

After his solo summer, William seemed to re-commit by October as their fourth year at St. Andrews began. Kate was invited to Prince Charles' 56th birthday party that November and joined William at Klosters in March 2005.

But during the school year Kate also found out that over the summer William had gone to visit Isabella Anstruther-Gough-Calthorpe, the sister of one of his polo buddies, and she told him to lose her number.

By May, though, with the end of university looming, they were tentatively back together. They graduated on June 23, 2005.

The couple were anxious thinking about their no longer built-in living arrangement, William planning on joining the military the following year and Kate not yet convinced that he was really in it for the long haul.

"I'm only 22 for God's sake," William had told a reporter that April a few days before his father married Camilla, having been asked if marriage was on his mind as well. "I'm too young to marry at my age. I don't want to get married till I'm at least 28, or maybe 30."

Of course, it would have been the scandal of the year if Kate had talked to a reporter, so she pressed on, unable to have a public reaction—positive or negative—to her boyfriend's remarks.

But they had a lovely summer, traveling to Kenya together to visit Jecca Craig and steal away to a $1,500-a-night cottage at the Masai Lodge in Nairobi. That Christmas, Kate joined the royal family at Sandringham for their annual Boxing Day (Dec. 26) shoot.

The couple rang in 2006 together at Sandringham, then William took Kate on a private ski holiday to Klosters, minus the photographers who snapped away at the now-obvious couple. They even kissed on the mountain this time.

And with that, the engagement countdown began. For royal watchers and bookmakers, at least.

Kate moved into her own flat in London and got a job as an accessories buyer for British fashion retailer Jigsaw, while William got ready for the Royal Military Academy at Sandhurst, where he would train to be a helicopter pilot.

Prince Harry had started dating Chelsy Davy and was about to graduate from Sandhurst, having decided to go right into military training after Eton. Kate skipped the celebratory ball but joined Harry, Chelsy and William at a club the next night, where they ran up a $3,000 bar tab that turned into "on the house" for the VIP guests.

William and Kate spent spring break of 2006 in Mustique—"Prince William, Bikini-Clad Girlfriend Caused a Stir," read an ABC News headline—and that December she and her parents had front-row seats at her boyfriend's passing-out ceremony at Sandhurst. Charles and Camilla were there, as was Will's granny, the queen. Both Kate and the monarch wore red coats.

The couple seemed to be in the engagement home stretch. Kate started studying what others had done in her place—her place being, as far as she knew, on the precipice of joining the royal family—and fielded tips on how to handle the increased scrutiny. Charles' Clarence House press team now looked after Kate, too, and William's security team was her team whenever they were together. 

But at the end of 2006, William canceled on spending New Year's with Kate's family, who had booked a cottage in the Scottish town of Alyth for the occasion.

There had been no Christmas at Sandringham, either, though Kate had been invited to lunch—which was quite a big deal, as they weren't married, or even engaged, yet. But Kate was going to be out of town with her parents, thinking William would be joining them a week later. 

Instead, William had to leave for his first posting, with the Blues and Royals of the British Army's Household Cavalry, in Dorset on Jan. 8, 2007—the day before Kate's 25th birthday.

It was also right around that time that a piece in The Spectator heralded Kate as "THE NEXT PEOPLE'S PRINCESS." The paparazzi wouldn't leave her alone for a second after that.

"Miss Middleton should, like any other private individual, be able to go about her everyday business without this kind of intrusion," read a statement from the palace, sent at William's behest. "The situation is proving unbearable for all those concerned."

Behind the scenes, William was asking his father and the queen for advice about his future; both advised him not to rush into anything.

Meanwhile, the paparazzi were sorely disappointed if they were hoping to catch William and Kate together. Visits became few and far between once he went to Dorset. 

And then he was photographed enjoying an evening with friends, including other girls, at Boujis, an exclusive nightclub in London he had frequented with Kate. As in, William was in town, and not spending the evening with his supposedly serious girlfriend. Another night he was photographed with his arm around one girl and dancing with another at a club closer to his posting.

While he obviously was fiercely protective of Kate, William was also staring forever in the face. And the prince blinked.

Guessing that four years had been enough of a courtship, the papers were predicting that an engagement was forthcoming.

Instead, William broke up with Kate.

On March 31, 2007, they went on a double date with pals Hugh and Rose van Cutsem. On April 3, Kate was single again as she left for a trip to Ireland.

She was, understandably, devastated—but just as she didn't let William think he could swoop in out of nowhere and make out with her after the student fashion show in 2002, she wasn't going to let him (or, by then, all of Britain) think she was pining away for the prince.

Kate signed up for a charity rowing challenge with an all-girl crew and started training hard. "Kate was very down and I think the training became her therapy," Emma Sayle, the group's leader, recalled to Marcia Moody for her 2018 book Kate: A Biography. "Kate had always put William first and she said this was a chance to do something for herself."

She was even spotted one night being escorted home from a party by Willem Marx, an old beau from her days at Marlborough who had gone to Oxford while she chose St. Andrews.

Pippa moved in with her in London and they maintained a packed social schedule. Needless to say, Kate was never photographed looking any less than her best. She ended up on the cover of Hello!, no longer press-shy.

William, who despite more raucous nights out in the interim, was starting to regret his decision to break up, and in June 2007 he invited Kate to a costume party at his barracks.

He was again pressed into action by an impressive outfit, Kate dressed as a naughty nurse.

They quickly reconciled.

On June 24, 2007, Nicholl reported for the Mail on Sunday that Kate and William were indeed officially back together. On July 1, at the "Concert for Diana" at Wembley Stadium, Kate rocked out two rows behind William and Harry in the royal box.

Incidentally, no matter how unsure he was of what to do as his college graduation loomed, 22-year-old William had correctly guessed his future marrying age.

"I think at the time I wasn't very happy about it," Kate would calmly reflect on their two-month breakup in her 2010 engagement interview after a 28-year-old William proposed and slipped the sapphire and diamond ring that once belonged to Princess Diana on his intended's finger. "But actually it made me a stronger person. You find out things about yourself that maybe you hadn't realized. I think you can get quite consumed by a relationship when you're younger. I really valued that time for me as well, although I didn't think it at the time."

Added William, "We were both very young. We were both finding ourselves and being different characters. It was very much trying to find our own way and we were growing up so it was just a bit of space and it worked out for the better."

He can consider himself lucky that it did.

"She is an adoring mother, and she is contributing publicly in the way we would want her to," a royal household source said of Kate, talking to People in 2019. "You see it more and more. The young student has turned into our future Queen."

(Originally published April 29, 2019, at 3 a.m. PT)