Prince Philip, Duke of Edinburgh, and his longtime love the Queen look more harmonious than ever sitting companionably side by side in their favourite Windsor Castle drawing room - a picture of a pair who have weathered life's storms and celebrated great joys as a team. After almost 69 years of marriage, the royal duo posed for the portrait by renowned photographer Annie Leibovitz to mark Her Majesty's 90th birthday.
Yet the Prince's own birthday, when he turns 95 on 10 June, will pass off with relatively little fanfare, in accordance with his wishes. Since that day on November 20, 1947 when the Duke pledged to love and honour his princess-bride in a fairytale wedding that punctured the gloom of post-war Britain, he has stayed in the background, a steadfast support as his wife fulfils a vital role for the nation. On their golden wedding anniversary in 1997, the Queen praised his devotion, saying: "He has, quite simply, been my strength and stay all these years."
Age has not diminished his commitment one iota. As the longest serving consort of a monarch, he still carries out 250 engagements a year. On the 70th anniversary of the D-Day landings in 2014, he accompanied the sovereign to the commemorations in France. Then in 2015, there was a state visit to Germany and a trip to Malta for the Commonwealth Heads of Government meeting.
For the Trooping of the Colour ceremony on 11 June, which is the official summer birthday parade for the monarch, Philip is expected to be, once again, one step behind her as he has been all his life, with the same ramrod bearing that he learned during years of naval service.
On the few important occasions when he is not on hand – such as when a bout of ill-health forced him to miss the service of thanksgiving for her Diamond Jubilee in 2012 – his absence is as keenly felt as if a crown were to go missing from the Tower of London.
However, in the early days of their courtship no one could have predicted that the marriage would have gone on to be such an unqualified success. Philip was a Prince without a kingdom to call his own, having entered the world as Prince Philip of Greece in 1921 on the island of Corfu.
His father was Prince Andrew of Greece, the seventh child of the country's King George I, while his mother Princess Alice of Battenberg was a great-granddaughter of Queen Victoria.
Philip and his four older sisters endured a tumultuous childhood beset with trauma and dramas stemming from their family's exile from Greece in 1922. Princess Alice had been born deaf and suffered poor mental health. She was committed to a psychiatric clinic where she stayed for two years when Philip was eight.
This, coupled with an unreliable father who was often absent in the south of France, meant that the young royal was virtually orphaned. In 1937, the family suffered another blow when his sister Cecile, her husband and two of her sons were killed in an air crash.
Despite his difficult start, Philip emerged a strong, ambitious and formidable character. His good looks, combined with his status as a dashing young naval officer, set many ladies' hearts aflutter. But it was Britain’s young Princess Elizabeth who gave him the love and happy family atmosphere he sorely needed.
In 1939, when George VI visited Dartmouth Naval College with his family the Greek royal was asked to show 13-year-old Elizabeth around.
They kept in touch after the meeting, exchanging a series of heartfelt and romantic letters during World War II as Philip served with the British navy in the Indian Ocean and the Mediterranean.
He was mentioned in dispatches, and became at 21 one of the youngest first lieutenants in the Royal Navy. In this capacity he was second in command of the destroyer HMS Wallace.
During his leave, he would make frequent trips to London to visit Elizabeth and the Princess's governess, Marion Crawford, recalled how he would roar through the forecourt of Buckingham Palace in an MG sports car, "always in a hurry to see Lilibet", as her family called her.
On his return from battle when Elizabeth was 19, they officially started courting. Although he'd proved his worth during the conflict, the war hero with no home or fortune was an unlikely choice of regal companion.
Nevertheless, in April 1947, the King gave his blessing for a royal wedding. The groom wrote to his beloved's mother, Queen Elizabeth, of his good fortune. "I am sure that I do not deserve all the good things that have happened to me…. to have been spared in the war and seen victory. To have fallen in love completely and unreservedly."
In another letter to the Queen Mother, he wrote: "Cherish Lilibet? I wonder if that word is enough to express what is in me."
After the nuptials, Philip became His Royal Highness The Duke of Edinburgh. He had already renounced his Greek citizenship and adopted the name Mountbatten. This was taken from his maternal grandparents, who although members of the German royal family, had adopted British nationality and translated their surname Battenberg literally into English. Elizabeth and Philip went on to have four children; Prince Charles, born in 1948, followed by Princess Anne in 1950, and then, after a gap of ten years, Prince Andrew and finally Prince Edward.
Besides his family, the Duke's passions draw him in three main directions – the environment, equestrian pursuits and the welfare of young people.
Perhaps his greatest contribution has been the Duke of Edinburgh Award Scheme, which he launched in 1956 to provide youngsters with an opportunity for personal and professional discovery. The scheme has gone on to become one of the most successful youth programmes in the world, with more than six million young men and women gaining the award. He also lent his support to the World Wildlife Fund for Nature, and in his role as president from 1961 to 1982 toured the world to promote its cause.
During over 60 years in the spotlight, the Prince has become known for using quips to break up the routine of public engagements. He himself recognises that his jokes can be risky, concluding a tour of Australia and New Zealand in 1968 by saying: "As so often happens, I discover that it would have been better to keep my mouth shut."
Though his remarks can be controversial, the Queen appreciates his sense of humour. Prince Philip excels in his official role as Her Majesty's consort precisely because he knows that behind closed doors, he has the traditional role of head of their family. And one of the reasons their love has stood the test of time is their ability to laugh together – her husband can tease out genuine, unabashed mirth from the monarch.
He is the rock of his family. Princes William and Harry particularly value his advice and support. When William voiced doubts about walking behind his mother Princess Diana's coffin in 1997, it was his grandfather who helped reassure him. Philip, who was intimately acquainted with loss, offered to accompany the bereaved youngster in the most difficult journey he would ever have to take. "If I walk, will you walk with me?" he asked.
During a recent documentary about the Queen's life, Prince William spoke about his grandparents' bond while watching footage of the two of them smiling at one another during a photoshoot.
"I'd love to know their secret," he said. "I think it’s fantastic and I've regularly asked them both how they've managed it, because they are the most lovely couple. I hope Catherine and I have the same sort of future ahead of us, where we can be as happily married as they are after 68 years."