Prince Philip, the longest-serving royal consort in English history, died on Friday at the age of 99, according to Buckingham Palace. He was a constant presence at Queen Elizabeth II's side for ages.

The 94-year-old queen is mourning the death of the Duke of Edinburgh, whom she once described as her "strength and hold all these years. The Royal Family, like the rest of the country, is mourning his death.

In 1947, Philip, who is also recognized as the Duke of Edinburgh, married Elizabeth. After more than 20,000 public appearances, he announced his retirement in 2017. Philip was born in 1921 on the Greek island of Corfu and was a member of the Greek royal family. He was an active sportsman who enjoyed outdoor activities. He was the father of four daughters, the grandfather of eight grandchildren, and the great-grandfather of nine great-grandchildren.

He was the patron of hundreds of charities; created activities to assist British schoolchildren to indulge in challenging outdoor adventures and was a key figure in the upbringing of his four children, including the heir to the throne, Prince Charles.

Philip spent a month in hospital previously this year before returning to Windsor Castle on March 16. Her Majesty “The Queen” has declared the death of her beloved husband, His Royal Highness “Prince Philip, Duke of Edinburgh, with great sadness,” the palace said.

Philip, who was made Duke of Edinburgh on his wedding day, saw his sole role as assisting his wife, who began her rule as Britain withdrew from empire and guided the empire through decades of declining social deference and UK influence into a modern world where people demand affection from their idols.

“He assured me the first day as he offered me my position, that his job was not to let her down,” Michael Parker, an old navy friend, and former private secretary of the prince said in the 1970s.

The queen, known for her modesty and dislikes public displays of affection, once referred to him as "her rock" in public. Philip called his wife Lilibet in private but referred to her as "The Queen" when speaking with others.

Philip's reputation evolved from that of a charming, dashing athlete to that of an arrogant, cruel curmudgeon. In his later years, he was known as a rueful and philosophical observer of the times, an old, craggy-faced man who kept his military stance despite ill health.

Philip was given a central role in the successful Netflix series "The Crown," with a mildly racy, swashbuckling image. He never said anything about it in media, but many Britons, including younger viewers who knew him, were moved by the portrayal.

Philip's situation was difficult because the husband of a sovereign queen has no formal position, and his life was marked by peculiar inconsistencies between his public and private responsibilities. In public, he walked three laps behind his wife to show respect for the queen, but in private, he was the family's head. Despite this, his son Charles, as heir to the throne, had a higher income and access to high-level government documents that Philip was not allowed to see.

“Lawfully, I don't exist,” said Philip, who surpassed Queen Charlotte, who married King George III in the 18th century, as the longest-serving prince in British history in 2009. He struggled to find his place in society regularly, a conflict that echoed in his grandson Prince Harry's decision to abdicate royal duties.

In an interview with the BBC on his 90th birthday, he said, "There was no context." “When I asked people, ‘what do you want me to do?”.