Buckingham Palace officials said Friday Prince Philip, the husband of Queen Elizabeth II, has died aged 99.
The palace said "it is with deep sorrow that Her Majesty The Queen has announced the death of her beloved husband, His Royal Highness The Prince Philip, Duke of Edinburgh."
The announcement said Philip "passed away peacefully this morning at Windsor Castle."
Speaking from Downing Street, UK Prime Minister Boris Johnson said he received the news of the duke's death "with great sadness".
Johnson said Prince Philip "inspired the lives of countless young people," adding that "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."
Philip spent a month in hospital earlier this year before being released on March 16 to return to Windsor Castle.
Philip, also known as the Duke of Edinburgh, married Elizabeth in 1947 and was the longest-serving consort in British history. He retired from public engagements in 2017 after carrying out more than 20,000 of them.
Philip was a member of the Greek royal family and was born on the Greek island of Corfu in 1921. He was an avid sportsman who loved country pursuits. He had four children, eight grandchildren and nine great-grandchildren.