Her Majesty Queen Elizabeth II, along with the royal family and United Kingdom will enter an eight-day period of mourning after her husband, Prince Philip, The Duke of Edinburgh, died in his sleep at the age of 99. The royal couple, who weathered many storms, including her unexpected ascension to the throne, had been married for 73 years.

In an official statement available on the website, the royal family said, “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 Royal Family join with people around the world in mourning his loss.”

The Duke had recently been in the hospital suffering from an infection and heart related issues. He died peacefully in Windsor Castle with the Queen, who has been quarantining in the royal residence.

A constant presence at her side, The Duke spent almost his entire life in service to his wife, the United Kingdom and the Commonwealth.

BBC royal correspondent Nicholas Witchell said that his passing is “a moment of real national sadness” and “ a moment of sadness, most particularly of course, for the Queen losing her husband of 73 years—a bigger span of years than most of us can imagine.”

He continued, Prince Philip made “a huge contribution to the success of the Queen’s reign,” describing The Duke as “utterly loyal in his belief in the importance of the role that the Queen was fulfilling—and in his duty to support her.”

“It is the importance of the solidarity of that relationship, of their marriage, that was so crucial to the success of her reign,” he said.

The Queen and the Duke were married on November 20, 1947, where he was presented with the title of the Duke of Edinburgh, though he was royal from birth, having been a Prince of Greece and Denmark and the longest-living of Queen Victoria’s great-great grandchildren. He is also in line to roughly 16 dynasties throughout Europe and his DNA was used to help properly identify the remains of former Tsar Nicholas II and the rest of his family, who were executed by the Bolsheviks in 1918.

The title of Duke of Edinburgh, which was given to Prince Philip as a reflection of his future role as consort to then Princess Elizabeth, will now reportedly be passed on to his youngest son, Prince Edward, Earl of Wessex.

Though The Duke did retire from most royal duties in 2017, the national and international reaction to his passing reflects a life well-lived and his influential service to the country.

British Prime Minister Boris Johnson said, “He was the longest-serving consort in history and one of the last surviving people in this country to have served in the Second World War,” Mr. Johnson said in a statement read in somber tones.

In reference to Prince Philip’s hobby of horse driving, one he shared with granddaughter Lady Louise Windsor, Mr. Johnson added that “like the expert carriage driver that he was, he helped to steer the royal family and the monarchy so that it remains an institution indisputably vital to the balance and happiness of our national life.”

In a statement, former president George W. Bush said, “Laura and I are saddened to learn of the passing of Prince Philip, the Duke of Edinburgh. Throughout his long and remarkable life, he devoted himself to worthy causes and to others.”

Bush continued describing that Prince Philip “represented the United Kingdom with dignity and brought boundless strength and support to the sovereign.”

“Laura and I are fortunate to have enjoyed the charm and wit of his company, and we know how much he will be missed,” the former president continued.

“We join those around the world offering heartfelt condolences to Her Majesty Queen Elizabeth II and the entire Royal Family,” he said.

King Willem-Alexander, Queen Maxima and Princess Beatrix, who abdicated the throne to her son as part of the country’s century long tradition, said, “It is with great respect that we remember His Royal Highness Prince Philip. Throughout his long life, he committed himself with dedication to the British people and to his many duties and responsibilities. His lively personality never ceased to leave an unforgettable impression. Our deepest and most heartfelt sympathy goes out to Her Majesty Queen Elizabeth and all the members of the Royal Family.”

Arrangements for Prince Philip’s funeral, known by the code name Forth Bridge, will be made available in the coming days, but will likely be smaller than expected.

Marriage is a life-long commitment, and one that is well-demonstrated by the union of The Queen and The Duke, who have four children, eight grandchildren and ten great-grandchildren. He will be deeply missed by his family, but most importantly by the woman who he has stood faithfully behind and supported for over 70 years, his precious Lilibet.