Prince Philip's death Friday at the age of 99 marked the end of an era in Britain's royal family.
Philip was a steadfast supporter of his wife of 73 years, Queen Elizabeth, and a consistent presence in public life.
When he officially retired from royal duties in 2017 at age 96, Philip had completed more than 22,000 solo engagements since 1952, given 5,496 speeches in his travels to more than 76 countries, authored 14 books, served as patron to 785 organizations and made 637 solo overseas visits, according to Buckingham Palace.
MORE: Prince Philip dies: 8 things to know about Queen Elizabeth's husbandPhilip was also a constant presence in the life of his family. In addition to Queen Elizabeth, the duke is survived by four children, eight grandchildren and 10 great-grandchildren.
Upon his death, leaders from around the world reflected on Philip's 99 years of life and the legacy he leaves behind.
Buckingham Palace announced Philip's death with a statement that read, in part, "The Royal Family join with people around the world in mourning his loss."
The statement was shared on the royal family's website, as well as the social media accounts of royal family members, including Philip's grandson, Prince William, and his wife, Duchess Kate.
The websites of the royal households and the profile photos on the royals' social accounts were also changed to honor Philip.
Harry and Meghan paid tribute to Philip on the website of Archewell, their nonprofit and production venture.
"Thank you for your service," read a message on the website, which was changed Friday to feature just the tribute to Philip. "You will be greatly missed."
Members of the royal family are not expected to issue further public comments as they continue their period of mourning.
Following tradition, Buckingham Palace also placed an announcement of Prince Philip’s death on the gates of the palace. Flags at the palace will be flown at half-mast from today until the morning of the day after the funeral service for Philip.
United States President Joe Biden and First Lady Jill Biden issued a statement Friday remembering Philip's legacy of family and service.
"On behalf of all the people of the United States, we send our deepest condolences to Her Majesty Queen Elizabeth II, the entire Royal Family, and all the people of the United Kingdom on the death of His Royal Highness Prince Philip, the Duke of Edinburgh. Over the course of his 99-year life, he saw our world change dramatically and repeatedly. 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," the statement read. "The impact of his decades of devoted public service is evident in the worthy causes he lifted up as patron, in the environmental efforts he championed, in the members of the Armed Forces that he supported, in the young people he inspired, and so much more. His legacy will live on not only through his family, but in all the charitable endeavors he shaped."
The statement continued, "Jill and I are keeping the Queen and to Prince Philip’s children, grandchildren, and great-grandchildren in our hearts during this time."
Vice President Kamala Harris also released a statement, writing, "His Royal Highness Prince Philip, Duke of Edinburgh, led a long, remarkable life—the hallmarks of which were loyalty and service. From his decorated service in the Royal Navy during World War II to his long marriage and partnership with Her Majesty, Queen Elizabeth II, he dedicated himself fully to his family, his country, and the Commonwealth. Whether he was promoting environmentalism or the wellbeing of military families, he brought a profound sense of purpose to all he did.
"Doug and I send our condolences to the Royal Family and the people of the United Kingdom," the statement said, referring to Harris's husband, Second Gentleman Doug Emhoff.
U.K. Prime Minister Boris Johnson spoke about Philip's life and legacy in comments delivered Friday outside 10 Downing Street in London.
"Prince Philip earned the affection of generations here in the United Kingdom, across the Commonwealth and around the world," Johnson said. "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."
Former U.S. president Barack Obama former first lady Michelle Obama issued a statement on the passing of Prince Philip, saying, "as the world mourns his loss, we send our warmest wishes and deepest sympathies to the Queen, their children, grandchildren, and great-grandchildren; and everyone who knew and loved this remarkable man."
"When we first met His Royal Highness Prince Philip, Duke of Edinburgh, he and Her Majesty Queen Elizabeth II had already been on the world stage for more than half a century — welcoming leaders like Churchill and Kennedy; Mandela and Gorbachev. As two Americans unaccustomed to palaces and pomp, we didn’t know what to expect," the Obamas said in their statement. "We shouldn’t have worried. The Queen and Prince Philip immediately put us at ease with their grace and generosity, turning a ceremonial occasion into something far more natural, even comfortable. Prince Philip in particular was kind and warm, with a sharp wit and unfailing good humor. It was our first introduction to the man behind the title, and in the years since, our admiration for him has only grown. We will miss him dearly."
"Like the Queen, Prince Philip saw world wars and economic crises come and go. The radio gave way to the television, and the television to the internet," the statement continued. "And through it all, he helped provide steady leadership and guiding wisdom. It has long been said that the United States and Great Britain have a special relationship — one that has been maintained and strengthened not just by presidents and prime ministers but by the Royal Family that has outlasted them all."
"At the Queen’s side or trailing the customary two steps behind, Prince Philip showed the world what it meant to be a supportive husband to a powerful woman. Yet he also found a way to lead without demanding the spotlight — serving in combat in World War II, commanding a frigate in the Royal Navy, and tirelessly touring the world to champion British industry and excellence," the statement said. "Through his extraordinary example, he proved that true partnership has room for both ambition and selflessness — all in service of something greater. As the world mourns his loss, we send our warmest wishes and deepest sympathies to the Queen, their children, grandchildren, and great-grandchildren; and everyone who knew and loved this remarkable man."
Former U.S. president George W. Bush said in a statement, “Laura and I are saddened to learn the passing of Prince Philip, the Duke of Edinburgh. Throughout his long and remarkable life, he devoted himself to worthy causes and to others. He represented the United Kingdom with dignity and brought boundless strength and support to the sovereign. Laura and I are fortunate to enjoyed the charm and wit of his company and we know how much he will be missed. We join those around the world offering heartfelt condolences to Her Majesty Queen Elizabeth II and the entire Royal Family.”
The British Army also shared news of the death of Philip, whose military career included service in the British Navy during World War II.
Australian Prime Minister Scott Morrison released a statement reflecting on Philip's service to Australia, a Commonwealth nation.
"Prince Philip was no stranger to Australia, having visited our country on more than 20 occasions," Morrison said in the statement. "Through his service to the Commonwealth he presided as patron or president of nearly 50 organizations in Australia. Given his own service, Prince Philip also had a strong connection with the Australian Defense Force."
MORE: Inside Queen Elizabeth, Prince Philip's 7-decade marriage"For 65 years, The Duke of Edinburgh’s Award scheme has encouraged over 775,000 young Australians to explore their leadership potential. Forty thousand young Australians are currently participating in the program," he said. "Australians send our love and deepest condolences to her Majesty and all the Royal family. The Commonwealth family joins together in sorrow and thanksgiving for the loss and life of Prince Philip. God bless from all here in Australia."
Sweden's King Carl XVI Gustaf remembered Philip as a "great friend" of his family.
“The Queen & I are deeply saddened to learn of the death of His Royal Highness The Duke of Edinburgh," he said in a statement. "Prince Philip has been a great friend of our family for many years, a relation we have deeply valued. His service to his country will remain an inspiration to us all. We offer our sincere condolences to Her Majesty The Queen, The Royal Family and the people of the United Kingdom."
India Prime Minister Narendra Modi remembered Philip's legacy of community service.
"My thoughts are with the British people and the Royal Family on the passing away of HRH The Prince Philip, Duke of Edinburgh," he said in a statement. "He had a distinguished career in the military and was at the forefront of many community service initiatives. May his soul rest in peace.“
Israeli Prime Minister Benjamin Neytanyahu said Philip will be missed "in Israel and across the world."
"I express my deepest condolences to Her Majesty Queen Elizabeth, Prince Charles, the Royal Family and the people of the United Kingdom on the passing of the Duke of Edinburgh," he said. "Prince Philip was the consummate public servant and will be much missed in Israel and across the world."
German Chancellor Angela Merkel remembered Prince Philip for his "sense of duty" and "straightforwardness."
"The death of Prince Philip fills me with great sadness," she said in a statement. "His friendship for Germany, his straightforwardness and his sense of duty will remain unforgotten. All our thoughts are with H.M. Queen Elizabeth and the Royal Family."
Russian President Vladimir Putin sent a telegram to Queen Elizabeth, writing, "Many important events in Russia’s newest history are connected with the name of His Royal Highness. He deservedly enjoyed respect among the British and international authority.”
This is a developing story. Please check back for updates.