The Duke of Edinburgh, as he was officially known, had been by his wife’s side throughout her 69-year reign, the longest in British history.
During that time he earned a reputation for a tough, no-nonsense attitude and a propensity for occasional gaffes.
“It is with deep sorrow that Her Majesty The Queen announces the death of her beloved husband, His Royal Highness The Prince Philip, Duke of Edinburgh,” the palace said in a statement.
“His Royal Highness passed away peacefully this morning at Windsor Castle. The Royal Family join with people around the world in mourning his loss.”
Flags at Buckingham Palace and at government buildings across the United Kingdom were lowered to half-mast and members of the public laid flowers outside Windsor Castle and Buckingham Palace.
Prince Charles, Philip and Elizabeth’s eldest son and heir to the British throne, visited the queen at Windsor on Friday afternoon, a royal source said.
A Greek prince, Philip married Elizabeth in 1947.
He went on to play a key role helping the monarchy to adapt to a changing world in the post-World War II period and behind the walls of Buckingham Palace was the one key figure the Queen could trust and turn to, knowing he could tell her exactly what he thought.
“He has, quite simply, been my strength and stay all these years,” Elizabeth, 94, said in a rare personal tribute to Philip in a speech marking their 50th wedding anniversary in 1997.
“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.”
Buckingham Palace said modified funeral and ceremonial arrangements were being considered by the Queen in light of COVID-19 restrictions in England that put a limit of 30 on the number of mourners.
“With the safety and wellbeing of the public in mind, and in accordance with government guidelines, members of the public are asked not to gather in crowds,” the palace said.
“Those wishing to express their condolences are asked to do so in the safest way possible, and not to gather at royal residences.”
An online condolence book has been set up on the royal family’s website.
The College of Arms, Britain’s heraldic authority, said there would be no state funeral or lying-in-state and Philip’s body would lie at rest at Windsor before a funeral in the castle’s St George’s Chapel.
However, its statement was later taken down and arrangements have yet to be officially confirmed.
Grandson Prince Harry and his wife Meghan became the first members of the royal family to issue a message of condolence.
“Thank you for your service… You will be greatly missed,” they said on the website of their Archewell Foundation.
British newspapers reported that Harry, whose interview with Oprah Winfrey alongside Meghan last month plunged the royals into their greatest crisis in decades, was likely to be among the small number present at the funeral.
During that latest crisis, Philip was in hospital where he spent four weeks having treatment for an infection and to have a heart procedure before returning to Windsor in early March.
He died two months before his 100th birthday.
The prince’s charm and disinclination to tolerate those he regarded as foolish or sycophantic earned him respect from some Britons.
But to others, his sometimes brusque demeanour made him appear rude and aloof.
Prime Minister Boris Johnson said Philip had helped to steer the royal family and the monarchy so they remained “indisputably vital to the balance and happiness of our national life”.
“It is to Her Majesty, and her family, that our nation’s thoughts must turn today,” Johnson said.
“Because they have lost not just a much-loved and highly respected public figure but a devoted husband and a proud and loving father, grandfather and, in recent years, great-grandfather.”
Tributes and condolences flooded in from across the UK and the world, including from US President Joe Biden.
“From his service during World War II, to his 73 years alongside the Queen, and his entire life in the public eye – Prince Philip gladly dedicated himself to the people of the UK, the Commonwealth and to his family,” Biden said.
Russian President Vladimir Putin noted in a condolence telegram to the Queen that Prince Philip was a historic personality.
“He deservedly enjoyed the respect of the Britons and the international community,” he said, adding that he wished strength for the Queen’s family “in light of the heavy loss”.
The UK armed forces will mark Philip’s death at noon on Saturday with a Death Gun Salute.
Artillery units in London, Edinburgh, Cardiff, Belfast and Gibraltar, and some navy warships, will fire their guns 41 times.
After completing more than 22,000 solo appearances, Philip retired from public life in August 2017 although after that he occasionally appeared at official engagements.
His last appearance was in July at a military ceremony at Windsor Castle, where he and the monarch have resided during COVID-19 lockdowns.
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