File photo dated 06/09/97 of (left to right) the Duke of Edinburgh, Prince William, Earl Althorp, Prince Harry and the Prince of Wales as they walked behind Diana, the Princess of Wales' funeral cortege. The anniversary, this year, of Diana, Princess of Wales's death follows a turbulent time for her sons, the Duke of Cambridge and the Duke of Sussex. The princess was killed suddenly in a car crash 23 years ago on August 31 1997 when William and Harry were only 15 and 12.