On a day filled with pomp and celebration, it was a poignant and solemn moment that told a story of its own.

Queen Elizabeth walked stoically, but alone, to her seat in St. Paul's Cathedral for a service of thanksgiving to mark her six decades on the throne.

Missing was her husband — the 90-year-old man who has been her "strength and stay" — and who has accompanied her on so many similar walks.

Prince Philip, famously outspoken, undoubtedly had a few choice words for his current circumstance — a hospital stay to fight a bladder infection — but his absence from Diamond Jubilee celebrations this week served to emphasize how much he has meant to his wife, and the monarchy, since their marriage in 1947.

Carolyn Harris, a royal expert at Queen's University in Kingston, Ont., says seeing the solitary figure of the Queen brought to mind "the degree to which the Queen and the Duke of Edinburgh have been seen as a unit throughout the reign."

Elizabeth has the public image of a married woman, Harris says, unlike the last queen to mark a Diamond Jubilee.

"The iconic image we have of Queen Victoria today is in black and her perpetual mourning for Prince Albert, whereas the current Queen is very much seen as part of marriage and as part of a team with the Duke of Edinburgh, so it's very different … to see her by herself at these events."

Philip and Elizabeth have had a "long and successful marriage," Harris says, noting that they have come to complement each other quite well.

Rocky start

That evolution had a rocky start.

Elizabeth's desire to marry a man she first set her eyes on at age 13 was not warmly welcomed by her parents, or the courtiers at Buckingham Palace.

King George VI and Queen Elizabeth were concerned that their daughter "was very young, at 21, to make this decision, and also that she was essentially marrying the first man that she met," says Harris, who writes a blog called The Royal Historian.

In the palace halls, there was much mumbling that it would be better for Elizabeth to settle on an English gentleman, rather than a foreign prince. (Philip was born in Corfu in 1921 as a prince of Greece and Denmark.)

In Elizabeth's steadfast plan to marry Philip, Harris sees a reflection of her "strength of character."

"This was who she loved and was determined to marry."

The significance of that determination has been noted by observers, as recently as this week.

'Wisdom of the Queen's choice'

"You only had to watch the Duke of Edinburgh during Sunday’s Diamond Jubilee river pageant to see the wisdom of the Queen’s choice," author Philip Eade wrote in the Daily Telegraph.

"A week short of his 91st birthday, the longest-serving consort in British history stood for more than three hours in the cold, waving and smiling, supporting his wife of 64 years — just as he had sworn he would at her coronation."

ii-1957-cp-220-1310499

The Queen and Prince Philip arrive in an open carriage to open Parliament in Ottawa on Oct. 14, 1957. (Associated Press)

For Harris, the success of the marriage is particularly interesting in light of the contrast in their backgrounds: Elizabeth came from a stable nuclear family (mom, dad and two kids), while Philip was from a family that broke down when he was quite young. His mother was ill periodically and in a sanitarium, and his father moved to Monte Carlo with his mistress.

"In marrying the Queen, [Philip] gained that sort of stable home life that he didn't have when he was younger, whereas to her he might have seemed like a breath of fresh air in the very traditional royal court she was part of," says Harris. "He was well-travelled and had served in the Second World War."

His naval career came to an end in 1952, when at the age of 29 he gave it up "so that he could support [Elizabeth] in her activities as Queen," says Harris.

While that support has become a hallmark of his character, Philip has also become known for a brash outspokenness that could grab larger headlines than his charitable works or his efforts to drive reform of the royal household itself. One of his more infamous utterances came while on a visit to China in 1986, when he told British students: "If you stay here much longer, you'll all be slitty-eyed."

Controversy in Canada

Sometimes, his outspokenness drew headlines in Canada. Harris points to a speech he gave to the Canadian Medical Association during a 1959 Royal Visit.

"The theme was that Canadians were out of shape and needed more physical exercise and he had statistics for how many Canadian men would fail an army medical," says Harris.

"It's a very mainstream topic to discuss now but in 1959 that was seen as a very controversial thing to discuss while touring Canada."

But observers say there is a lot more to the man than a penchant for off-colour remarks.

ii-awards-220-cp-8998804

Prince Philip presents the Duke of Edinburgh Awards to Canadian youth in Toronto on July 5, 2010. (Adrien Veczan/Canadian Press)

"He's a far more intelligent and far-thinking person than the caricature of the gaffe-prone curmudgeon that has become kind of the default perception thanks to a lot of the tabloids," says Sally Bedell Smith, whose biography, Elizabeth the Queen: The Life of a Modern Monarch, was published earlier this year.

"People at Buckingham Palace gave me a couple of books of speeches that he wrote back in the late '40s and early '50s … and I was really astonished at the range of his interests, that he was very involved in conservation, in science and technology and the importance of improving education in those areas, in the role of fitness in overall health, in things like an awareness of saving the rainforest decades before it was on everybody's radar," Bedell Smith said during a visit to Toronto in February.

Her list of Philip's eclectic interests goes on: an early adapter of computers and email, oil painting, designing jewelry, ornithology.

"He's had all these interests on his own," Bedell Smith says, "but he's also performed impeccably as her consort and he said … on the occasion of one of their big anniversaries, it might have been their diamond wedding anniversary four years ago, that supporting the Queen was the most important thing he ever did in his life."

Ready to wind down

Harris says Philip has also "tended to really exercise a leadership role" in reforms of the royal household.

'He is someone who doesn't take easily to compliments but he has, quite simply, been my strength and stay all these years, and I, and his whole family, and this and many other countries, owe him a debt greater than he would ever claim, or we shall ever know.'—Queen Elizabeth, Golden Wedding speech, 1997

Still, time marches on, and Philip himself has talked about "winding down" and cutting back on his royal duties.

"I reckon I've done my bit so I want to enjoy myself a bit now, with less responsibility, less frantic rushing about, less preparation, less trying to think of something to say," he said in an interview with the BBC last year.

Harris expects both the Queen and Philip won't be doing the same range of appearances that they have undertaken until now, and that their children and grandchildren will take on more prominent roles in Royal Family activities.

The Queen showed no signs of slowing down this week, though, as jubilee festivities continued.

After they wrapped up, she went to visit Philip in hospital. It may have been the first time she saw him in a couple of days, and it must have been disappointing that the man she called her "strength and stay" during her Golden Wedding anniversary in 1997, had  been unable to share with her more of the Diamond Jubilee events.