He overcame a turbulent early life to become a respected war hero who won the heart of the future queen.
Driven, forthright and prone to what the media often referred to as “gaffes”, he was the person Queen Elizabeth II relied upon above all others.
“He is someone who doesn’t take easily to compliments but he has, quite simply, been my main strength and stay all these years,” she said after celebrating her Golden Jubilee in 2002.
“And I owe him a debt greater than he would ever claim or we shall ever know.”
Born on June 10, 1921 on the island of Corfu to Prince Andrew of Greece and Princess Alice of Battenberg, Prince Philip was only 18 months old when his family fled first to France and then Britain.
Watch: Minute's Silence Observed for Prince Philip Outside Windsor Castle
At nine years old, his mother was committed, against her will, to a psychiatric clinic, after suffering a nervous breakdown.
Her children, including Philip, had been taken out for the day and returned that evening to find their mother gone. His father moved to the south of France and it was left to Alice’s elder brother and his wife to bring up the young boy. But Philip was virtually orphaned.
Sent off to boarding school at Gordonstoun, tragedy befell the family when his pregnant sister Cecile was killed in an aeroplane crash. It was left to the headmaster of the school to break the news to 16-year-old Philip. He recalled that the teenager did not break down. “His sorrow was that of a man,” he said.
Philip then joined the Royal Navy College at Dartmouth. It was while training as a navy cadet that he caught the eye of Princess Elizabeth, who was a distant cousin.
Their first significant meeting was engineered by his uncle Lord Louis Mountbatten who arranged for 13-year-old Elizabeth to be escorted by Philip, then 18, on a visit with her parents to the college in July 1939.
The dashing Greek prince impressed Princess Elizabeth and her sister Margaret by vaulting over a tennis net after a game of croquet and treating them to ginger biscuits and lemonade.
A friendship was born and on his subsequent visits to Buckingham Palace, Marion Crawford, the young princess’s governess, remembered seeing the Philip’s black MG sports car roaring into the forecourt of the palace “always in a hurry to see Lilibet”.
Elizabeth was smitten and started to take more trouble with her appearance and to play the tune People Will Say We’re In Love from the musical Oklahoma. She kept a photograph of Philip by her bed.
During the Second World War, Philip was an active member of the Royal Navy. Awarded a medal for bravery and mentioned in dispatches for his skill with the searchlights. In one attack, his quick-thinking saved the lives of many of his men on board the battleship Valiant when they were under attack.
By July 1947, Philip had become a British subject and renounced his right to the Greek and Danish thrones. Although many in royal circles found Philip “rather unpolished” and had misgivings about the match, the young princess was besotted and their engagement was announced.
They were married in November 1947 at Westminster Abbey and spent their early married life in Malta, where Philip, now the Duke of Edinburgh, was stationed for two years. There, the young couple would hold hands in the back of a cinema and dance the night away to a hotel jazz band.
Philip continued to pursue his naval career, rising through the ranks to become second in command of the Fleet Destroyer HMS Whelp. But his life was to change on 6 February 1952 when Elizabeth became Queen.
Following her coronation in 1953, he assumed the role of full-time consort and devoted his life to supporting his wife. His first ever private secretary Michael Parker, a friend from the Navy, said: “He told me the first day he offered me my job that his job, first, second and last was never to let her down.”
With this in mind, Philip took control of the royal estates. “When the Queen succeeded, we chatted about who would do what,” he recalled. “I thought that if I could relieve her of the management of the estates, it would save her a lot of time.”
He was said to know every inch of Sandringham and all its staff. Always forward-thinking, he introduced a caravan park and a bird sanctuary and loved trying out new ideas. He was one of the very first people in the country to use solar panels.
Patron of more than 800 organisations including the World Wildlife Fund and National Maritime Museum, the Duke of Edinburgh was especially interested in scientific and technological research, conservation and the encouragement of sport.
Perhaps his greatest achievement was establishing the Duke of Edinburgh Awards Scheme in 1956 which has helped more than six million young people in 125 countries.
His most important role however has been that as a supportive husband. Lord Charteris, the Queen’s former private secretary once explained that: “Prince Philip is the only man in the world who treats the Queen as simply another human being. Strange as it may seem I believe she values that.”
In her Christmas 2017 address to the nation, the Queen praised her husband’s “unique sense of humour”.
Something of a practical joker, the Duke once chased his wife down a train corridor wearing joke false teeth during a 1951 Canada tour. At the Coronation in 1953, he lightened the load during the service by asking her: “Where did you get that hat?”
He used her nickname Lilibet, occasionally still called her “sausage” and gave her flowers every week. Their daughter-in-law, the Countess of Wessex once said of them: “They make each other laugh – which is, you know, it’s half the battle isn’t it?”
While the Queen is the head of state, Philip was the head of the Royal Family. During the most turbulent months of her marriage, he wrote heartfelt letters to Princess Diana and signed them “Fondest, Pa”.
At her funeral in 1997, clearly sensing the anguish of his beloved grandsons Princes William and Harry, he offered to accompany then behind the funeral cortege. “I’ll walk, if you walk” he told them.
At public engagements he would take the role of “ice breaker” for the Queen. Walking into rooms full of people, Elizabeth would sometimes have to gather herself.
But as portrait artist Michael Noakes recalled: “When Philip has seen that happening, he has taken over in a subtle way and made sure everything was OK. He says he can make people laugh within 15 seconds.”
When he turned 90 in 2011, he insisted on no fuss but the Queen bestowed on him a new title – Lord High Admiral, titular head of the Royal Navy. In the same year he joked in a letter to the magazine that he appreciated being named: “Consort of the Year”.
In August 2017, at the age of 96 he made his 22,219th sole engagement before retiring from public life. Even then, quipping that: “I’m discovering what it’s like to be on your last legs.”
By his retirement, he had given 5,496 speeches, written 14 books and gone on 637 solo visits overseas.
He retired to Wood Farm on the Sandringham Estate, and lived there most of the time, painting and responding to letters.
But he moved to Windsor Castle to be near his dear Lilibet during the 2020 coronavirus pandemic, particularly during the lockdowns in the UK.
They marked his 99th birthday and their 73rd wedding anniversary in various levels of lockdown, reducing their staff numbers as they stayed in their Berkshire home.
He even carried out a rare public duty from there in 2020, as he handed over a military appointment to his daughter-in-law Camilla, in a very socially distanced ceremony.
Plans were under way for his 100th birthday, with his desire for a quiet and no-fuss event to mark the milestone.
Watch: Prince Philip Funeral: Royal Procession Behind Duke's Coffin