By Michael Holden, William James and Andy Bruce

LONDON (Reuters) -Prince Philip, Queen Elizabeth’s husband who helped modernise the monarchy and steer the British royal family through repeated crises during seven decades of service, died on Friday at Windsor Castle. He was 99.

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. Further announcements will be made in due course. The Royal Family join with people around the world in mourning his loss.”

Flags at Buckingham Palace and at government buildings across Britain were lowered to half-mast and within an hour of the announcement the public began to lay flowers outside Windsor Castle and Buckingham Palace.

The royal family’s website was also shut down, replaced by a photo of Philip and the announcement of his death.

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 Two 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.”

The College of Arms, Britain’s heraldic authority, said there would be no state funeral or lying-in-state, reflecting Philip’s well-known aversion to making a fuss and COVID-19 restrictions in England.

“His Royal Highness’s body will lie at rest in Windsor Castle ahead of the funeral in St George’s Chapel. This is in line with custom and with His Royal Highness’s wishes,” it said in a statement.

“It is regretfully requested that members of the public do not attempt to attend or participate in any of the events that make up the funeral.”

Philip spent four weeks in hospital earlier this year for treatment for an infection and to have a heart procedure, but returned 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. He was a delight to newspaper editors keen to pick up on any stray remark at official events.

The former naval officer, who served in the Royal Navy during the war and was mentioned in dispatches for bravery, admitted he found it hard to give up the military career he loved and to take on the job as the monarch’s consort, for which there was no clear-cut provision.

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.”

HEAD OF THE FAMILY

In private, the prince was regarded as the head of his family, but protocol obliged the man dubbed “the second handshake” to spend his public life literally one step behind his wife.

“There was no precedent. If I asked somebody ‘what do you expect me to do?’, they all looked blank – they had no idea, nobody had much idea,” he said in an interview to mark his 90th birthday.

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, the royal palace west of London where he and the monarch have resided during COVID-19 lockdowns.

“On the occasions when I met him, I was always struck by his obvious joy at life, his enquiring mind and his ability to communicate to people from every background and walk of life,” Archbishop of Canterbury Justin Welby said.

QUEEN WITHOUT PHILIP

Philippos Schleswig-Holstein Sonderburg-Glucksburg was born on a dining room table on the Greek island of Corfu on June 10, 1921, the fifth child and only son of Prince Andrew of Greece.

He married the queen, then Princess Elizabeth, at Westminster Abbey on Nov. 20, 1947, five years before she came to the throne in 1952.

The couple, who were third cousins, had four children, Prince Charles, the heir to the throne, Princess Anne, and Princes Andrew and Edward.

They celebrated their 72nd anniversary on the same day that Andrew stepped down from public duties over the controversy surrounding his association with the disgraced late U.S. financier Jeffrey Epstein, one of a number of crises the family have faced.

The death of the queen’s husband and closest confidant will raise questions over whether she might consider abdication, but royal commentators see little or no chance of this.

In recent years, the queen has reduced her official engagements and passed many royal duties and patronages to Prince Charles, his son William and other senior royals. But she still carries out the most symbolic of the monarchy’s duties, such as the opening of parliament.

Some royal watchers say Philip’s declining health has played a role in some of the monarchy’s recent travails, such as the crisis surrounding the decision by Charles’ younger son Prince Harry and his wife Meghan to give up their royal roles.

“The main lesson that we have learned is that tolerance is the one essential ingredient of any happy marriage,” Philip said in a speech in 1997.

“It may not be quite so important when things are going well, but it is absolutely vital when things get difficult. You can take it from me that the queen has the quality of tolerance in abundance.”