For there has only ever been one man for Elizabeth. And Philip as the family’s kingpin has been unstinting in his support of his wife, both in public and in private.
There have at times been difficult periods, including crises that seemed to threaten the future of the monarchy, and occasional embarrassments caused by Philip’s plain speaking, but he has always been by her side.
She was just 13 when she met dashing young Philip, Prince of Greece, but the princess was smitten and set her heart on him.
It was July 22, 1939, and the King, Queen and their two daughters were to tour the Royal Naval College at Dartmouth.
When they arrived, the college was in the grip of a mumps outbreak, and the young princesses were kept at a safe distance in the house of the college’s captain, Admiral Sir Frederick Dalrymple-Hamilton.
The senior cadet assigned to entertain them was Philip, himself only 18.
Sixty years later, Elizabeth paid a heartfelt public tribute, saying: “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, in this and many other countries, owe him a debt greater than he would ever claim or we shall ever know.”
His importance is not just in the advice or support he gives the monarch, but also his presence during long overseas tours and engagements at home.
In private, Philip is the head of the household, with his wife deferring all important family decisions to him – characteristic of the royal couple’s generation.
This enduring romance and blossomed after that very first meeting, as senior courtiers discreetly established whether
Philip would be a suitable consort for the future Queen.
His credentials were impeccable – he was the son of Prince Andrew of Greece, and the nephew of Lord Louis Mountbatten, already a favourite in royal circles.
Elizabeth and Philip began corresponding, and met on several more occasions, including a tea party aboard the royal yacht where Mountbatten played Cupid.
Like countless other young women whose beaus were at war, Elizabeth worried about Philip, especially when he saw active service against German, Italian and Japanese forces.
But home leave brought him back to Elizabeth, and at Christmas 1943, Philip was invited to stay with the Royal Family at Windsor.
Mountbatten pulled strings at the Admiralty, and Philip was given a shore posting so that he could see Elizabeth more often.
By war’s end, there was widespread speculation about the romance and George VI, concerned that his daughter was too young for marriage, took her on his lengthy tour of South Africa in 1946, decreeing that there would be no engagement until she was 21.
The announcement came two months after her birthday, on July 10 1947.
The wedding took place on November 20, 1947, and it was a welcome splash of colour and good cheer for a Britain battered and exhausted by the long war.
The glamorous young royal couple caught the public’s imagination, and hundreds of thousands turned out to pack the streets around Westminster Abbey, as the day dawned cold but clear.
The 21-year-old bride-to-be appeared nervous throughout the ceremony until her new husband led her out from the chapel of St Edward the Confessor, where the registers were signed.
Then, as she passed her parents, she lifted her eyes and smiled.
The delighted crowds headed for Buckingham Palace where the newly-weds appeared on the balcony to huge cheers.
It was a scene to be repeated again and again throughout her historic reign.