Queen Elizabeth II and Prince Philip attend the wedding of Princess Eugenie and Jack Brooksbank at St George's Chapel on October 12, 2018 in Windsor, England. Getty Images
Lieutenant Philip Mountbatten, prior to his marriage to Princess Elizabeth, saluting as he resumes his attendance at the Royal Naval Officers School at Kingsmoor, England, on July 31, 1947. Getty Images
Philip Mountbatten, prior to his marriage to Princess Elizabeth, batting at the nets during cricket practice while in the Royal Navy, on July 31, 1947. Getty Images
From left: King George VI, Princess Margaret, Lady Mary Cambridge, Princess Elizabeth, Philip Mountbatten, Queen Elizabeth and Queen Mary on the balcony at Buckingham Palace after the wedding of Princess Elizabeth and Philip Mountbatten in London, England, on November 20, 1947. Getty Images
Prince Philip, Duke of Edinburgh, dancing with Wren Petty Officer Patricia Kelly aboard the HMS Chequers, on November 27, 1949. Getty Images
Princess Elizabeth and Prince Philip with their baby daughter, Princess Anne, following her christening at Buckingham Palace in London, England, on October 23, 1950. Getty Images
Queen Elizabeth II and Prince Philip being welcomed by a Kandyan chief during their royal tour in Kandy, Sri Lanka, on April 23, 1954. Getty Images
Prince Charles, left, Prince Philip, centre, and Princess Anne, right, visit the Acropolis in Greece on September 16, 1964. Getty Images
Prince Philip plays polo at Windsor Park in London, England, on July 28, 1967. Getty Images
Prince Philip and Queen Elizabeth II wave to crowds during the Garter Procession at Windsor Castle in London, England, on June 16 1969. Getty Images
From left: Princess Anne, Prince Philip, the Queen Mother and Queen Elizabeth II at the Derby at Epsom Downs Racecourse, Surrey, on June 2, 1971. Getty Images
Prince Philip, Duke of Edinburgh, driving a carriage in England on May 28, 1975. Getty Images
Queen Elizabeth II and Prince Philip during the Royal Progress trip via boat down the River Thames from Greenwich to Lambeth in London, England, on June 9, 1977. Getty Images
Prince Charles and Lady Diana Spencer with Queen Elizabeth II and Prince Philip, on the balcony at Buckingham Palace after their marriage ceremony at St Paul's Cathedral on July 29, 1981. Getty Images
Queen Elizabeth II and Prince Philip pose in the grounds of Sandringham House, England, on February 6, 1982, to mark the 30th anniversary of the Queen's accession to the throne. Getty Images
Queen Elizabeth II visits the Great Wall of China with Prince Philip on October 13, 1986. Getty Images
Founding Father Sheikh Zayed, Queen Elizabeth II, the Queen Mother and Prince Philip in London, England, on July 18, 1989. National Archives supplied by the Ministry of Presidential Affairs
Prince Philip, Duke of Edinburgh, at the helm of the yacht 'Yeoman XXVIII' on July 31, 1993. Getty Images
Prince Philip, Duke of Edinburgh, arrives at Cambridge University, England, for an honorary doctorates ceremony on June 9, 1994. Reuters
Queen Elizabeth II, George W Bush, Laura Bush and Prince Philip pose in the music room at Buckingham Palace on November 19, 2003 in London, England. Getty Images
Queen Elizabeth II and Prince Phillip officially open the new Stock Exchange building at Paternoster Square, on July 27, 2004 in London, England. Getty Images
Queen Elizabeth II and Prince Philip stand on the balcony of Buckingham Palace after attending the Trooping the Colour ceremony to mark the Queen's official birthday at Horse Guards Parade on June 12, 2004 in London, England. Getty Images
Queen Elizabeth and Prince Philip with Jacques Chirac and Bernadette Chirac before attending a state banquet on November 18, 2004 at Windsor Castle, England. Getty Images
Queen Elizabeth II and Prince Philip watch the flypast of British and US Second World War aircraft from the Buckingham Palace balcony on National Commemoration Day on July 10, 2005 in London, England. Getty Images
Queen Elizabeth II and Prince Philip walk through Windsor, London, on April 21, 2006. Getty Images
Prince Philip, Duke of Edinburgh, greets Prathibha Devi Singh Patil (not pictured) – the 12th President of India – on October 27, 2009, in Windsor, England. Getty Images
Queen Elizabeth II and Prince Philip leave St George's Chapel at Windsor Castle after attending the annual Order of the Garter Service on June 13, 2011 in Windsor, England. Getty Images
Prince Philip, Duke of Edinburgh, attends the Braemar Highland Games at The Princess Royal and Duke of Fife Memorial Park on September 1, 2012 in Braemar, Scotland. Getty Images
Queen Elizabeth ll and Prince Philip, Duke of Edinburgh, make an official visit to Baker Street Underground Station on March 20, 2013 in London, England. Getty Images
Prince Philip, Duke of Edinburgh, attends the Driving for the Disabled event during the Royal Windsor Horse Show at Home Park on May 15, 2014 in Windsor, England. Getty Images
Queen Elizabeth II and Prince Philip arrive for a state banquet in their honour at Schloss Bellevue palace on June 24, 2015 in Berlin, Germany. Getty Images
Prince Philip visits the British Airways i360 attraction in Brighton, England, where he took a ride on the world's first vertical cable car on October 28, 2016. Getty Images
Queen Elizabeth II and Prince Philip attend a service at St Paul's Cathedral to mark the 100th anniversary of the Order of the British Empire on May 24, 2017 in London, England. Getty Images
Queen Elizabeth II and Prince Philip attend the wedding of Princess Eugenie and Jack Brooksbank at St George's Chapel on October 12, 2018 in Windsor, England. Getty Images
Lieutenant Philip Mountbatten, prior to his marriage to Princess Elizabeth, saluting as he resumes his attendance at the Royal Naval Officers School at Kingsmoor, England, on July 31, 1947. Getty Images
Philip Mountbatten, prior to his marriage to Princess Elizabeth, batting at the nets during cricket practice while in the Royal Navy, on July 31, 1947. Getty Images
From left: King George VI, Princess Margaret, Lady Mary Cambridge, Princess Elizabeth, Philip Mountbatten, Queen Elizabeth and Queen Mary on the balcony at Buckingham Palace after the wedding of Princess Elizabeth and Philip Mountbatten in London, England, on November 20, 1947. Getty Images
Prince Philip, Duke of Edinburgh, dancing with Wren Petty Officer Patricia Kelly aboard the HMS Chequers, on November 27, 1949. Getty Images
Princess Elizabeth and Prince Philip with their baby daughter, Princess Anne, following her christening at Buckingham Palace in London, England, on October 23, 1950. Getty Images
Queen Elizabeth II and Prince Philip being welcomed by a Kandyan chief during their royal tour in Kandy, Sri Lanka, on April 23, 1954. Getty Images
Prince Charles, left, Prince Philip, centre, and Princess Anne, right, visit the Acropolis in Greece on September 16, 1964. Getty Images
Prince Philip plays polo at Windsor Park in London, England, on July 28, 1967. Getty Images
Prince Philip and Queen Elizabeth II wave to crowds during the Garter Procession at Windsor Castle in London, England, on June 16 1969. Getty Images
From left: Princess Anne, Prince Philip, the Queen Mother and Queen Elizabeth II at the Derby at Epsom Downs Racecourse, Surrey, on June 2, 1971. Getty Images
Prince Philip, Duke of Edinburgh, driving a carriage in England on May 28, 1975. Getty Images
Queen Elizabeth II and Prince Philip during the Royal Progress trip via boat down the River Thames from Greenwich to Lambeth in London, England, on June 9, 1977. Getty Images
Prince Charles and Lady Diana Spencer with Queen Elizabeth II and Prince Philip, on the balcony at Buckingham Palace after their marriage ceremony at St Paul's Cathedral on July 29, 1981. Getty Images
Queen Elizabeth II and Prince Philip pose in the grounds of Sandringham House, England, on February 6, 1982, to mark the 30th anniversary of the Queen's accession to the throne. Getty Images
Queen Elizabeth II visits the Great Wall of China with Prince Philip on October 13, 1986. Getty Images
Founding Father Sheikh Zayed, Queen Elizabeth II, the Queen Mother and Prince Philip in London, England, on July 18, 1989. National Archives supplied by the Ministry of Presidential Affairs
Prince Philip, Duke of Edinburgh, at the helm of the yacht 'Yeoman XXVIII' on July 31, 1993. Getty Images
Prince Philip, Duke of Edinburgh, arrives at Cambridge University, England, for an honorary doctorates ceremony on June 9, 1994. Reuters
Queen Elizabeth II, George W Bush, Laura Bush and Prince Philip pose in the music room at Buckingham Palace on November 19, 2003 in London, England. Getty Images
Queen Elizabeth II and Prince Phillip officially open the new Stock Exchange building at Paternoster Square, on July 27, 2004 in London, England. Getty Images
Queen Elizabeth II and Prince Philip stand on the balcony of Buckingham Palace after attending the Trooping the Colour ceremony to mark the Queen's official birthday at Horse Guards Parade on June 12, 2004 in London, England. Getty Images
Queen Elizabeth and Prince Philip with Jacques Chirac and Bernadette Chirac before attending a state banquet on November 18, 2004 at Windsor Castle, England. Getty Images
Queen Elizabeth II and Prince Philip watch the flypast of British and US Second World War aircraft from the Buckingham Palace balcony on National Commemoration Day on July 10, 2005 in London, England. Getty Images
Queen Elizabeth II and Prince Philip walk through Windsor, London, on April 21, 2006. Getty Images
Prince Philip, Duke of Edinburgh, greets Prathibha Devi Singh Patil (not pictured) – the 12th President of India – on October 27, 2009, in Windsor, England. Getty Images
Queen Elizabeth II and Prince Philip leave St George's Chapel at Windsor Castle after attending the annual Order of the Garter Service on June 13, 2011 in Windsor, England. Getty Images
Prince Philip, Duke of Edinburgh, attends the Braemar Highland Games at The Princess Royal and Duke of Fife Memorial Park on September 1, 2012 in Braemar, Scotland. Getty Images
Queen Elizabeth ll and Prince Philip, Duke of Edinburgh, make an official visit to Baker Street Underground Station on March 20, 2013 in London, England. Getty Images
Prince Philip, Duke of Edinburgh, attends the Driving for the Disabled event during the Royal Windsor Horse Show at Home Park on May 15, 2014 in Windsor, England. Getty Images
Queen Elizabeth II and Prince Philip arrive for a state banquet in their honour at Schloss Bellevue palace on June 24, 2015 in Berlin, Germany. Getty Images
Prince Philip visits the British Airways i360 attraction in Brighton, England, where he took a ride on the world's first vertical cable car on October 28, 2016. Getty Images
Queen Elizabeth II and Prince Philip attend a service at St Paul's Cathedral to mark the 100th anniversary of the Order of the British Empire on May 24, 2017 in London, England. Getty Images
Queen Elizabeth II and Prince Philip attend the wedding of Princess Eugenie and Jack Brooksbank at St George's Chapel on October 12, 2018 in Windsor, England. Getty Images