Video report by ITV News Correspondent Rachel Younger
After over 70 years with him by her side, Queen Elizabeth must now face a future without Philip, the man she once honoured as her "strength and stay", the longest serving royal consort in British history.
Elizabeth II has become the first reigning widow monarch since Queen Victoria, who was so devastated by the death of Prince Albert, she withdrew almost entirely from public life for 40 years and become known as the ‘Widow of Windsor’.
Elizabeth II is unlikely to follow in the footsteps of her great-great grandmother but will be looking to the younger generation to support her as she continues to perform her royal engagements solo.
A life in public service was set for the Queen and Prince Philip from the beginning of their relationship, their personal roles evolving from young sweethearts to married parents and eventually to great-grandparents in an expanding royal dynasty.
ITV News Royal Editor Chris Ship reflects on the partnership between The Queen and Prince Philip
Theirs was a union rooted in a wartime romance following an encounter at the Royal Naval College in Dartmouth in 1939 when the queen was just 13.
Lady Pamela Hicks, Prince Philip’s cousin recalls the moment Elizabeth first met the dashing Duke: "I think she fell in love from that day onward. And then of course, when she blossomed into a very beautiful young woman with that dazzling complexion, so he fell too.
"He of course really looked like a kind of Viking God - very tall, very blond, marvellous-looking, all the girls in England were in love with him."
Two years after the end of the Second World War, the nation, in the grip of post-war austerity, celebrated the marriage of the royal couple.
It was the start of an enduring partnership that would see Philip stand by his wife’s side through triumph and tragedy.
The early days of their marriage were relatively carefree for a couple whose lives would become defined by public duty.
They moved to Malta where the Duke had been put in command of a Royal Navy warship and were able to carve out a degree of time away from the public gaze.
But within five years, their lives irrevocably changed.
Elizabeth's father George VI died in February 1952 while the young couple were on a royal tour in Kenya. Elizabeth left a princess and arrived back to the UK a Queen.
She was just 25; Philip, then 31, vowed to sacrifice his own naval career to become her lifelong consort.
Lady Hicks recalled the moment the new Queen of England returned home to a very different life.
"As we came over London airport, we could see [Winston] Churchill and [Clement] Attlee and all the government and all the Cabinet there," she told ITV News.
"One suddenly thought - there's this 25-year-old woman with her husband in the Navy, extremely successful - about - obviously would go to the top in his profession. Two small children and this had all come to an end.
"Their private life is finished. They now are public servants for the rest of their lives."
It was the start of an extraordinary public life that saw the young royal couple complete tour after tour, year after year; their journeys took them to 120 countries, travelling the world the equivalent of 42 times.
And wherever they were, from India's Taj Mahal in 1961 to the Great Wall of China in 1986, the Duke always by the Queen’s side.
Despite the public attention, as a couple, Elizabeth and Philip guarded their privacy and very rarely showed emotion in public beyond a peck on the cheek or a shared joke.
But behind the closed Palace doors the prince's sense of fun and ability to put the Queen at ease helped to relieve the pressure on many formal occasions.
And while they rarely shared emotion or affection in public, the Queen was in no doubt of the importance that Philip played.
Her Majesty paid tribute to him at the Golden Wedding celebrations in 1997, saying she, her family and the Commonwealth owed him a debt "greater than he would ever claim" after years of service.
"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 will ever claim or that we shall ever know," she said.
Those years continued for more than two decades but both knew one was destined to outlive the other.
And his willingness to embrace change and technology helped them take the Monarchy forward together.
At the age of 96, Prince Philip was ready for a break, stepping back from public life with the Queen's blessing, after more than 22,000 engagements together.
And now, it is the Queen who will see out her historic reign without her husband and consort by her side.
But with the family she and Philip nurtured, she will hope to ensure that while she is widowed, until the end of her life she will have her family to walk with her.