Princess Elizabeth was born at 2.40am on 21 April 1926. She was the first child of the Duke and Duchess of York, who became King George VI and Queen Elizabeth. After King George VI died, his wife became Queen Elizabeth the Queen Mother.
Princess Elizabeth with her parents in 1929, and, below, in 1930.
Princess Elizabeth reading a book with her sister Margaret sitting by a window with a corgi called Jane in 1940 (left), and the two sisters acting together in a pantomime of Cinderella at Windsor Castle.
Princess Elizabeth writing at her desk in Windsor Castle in 1944 (left), and addressing an assembly of the Governors Court at the Queen Elizabeth Hospital for Children as their president in her first solo engagement (right).
Princess Elizabeth in her lounge at Buckingham Palace in 1946 (left), and standing by a window in the state apartments at the palace (right).
Princess Elizabeth and Prince Philip, Duke of Edinburgh, at Buckingham Palace in 1947 shortly before their wedding. The princess is wearing her engagement ring for the first time.
Princess Elizabeth and Prince Philip make their way down the aisle of Westminster Abbey, London, on their wedding day on 20 November 1947.
Princess Elizabeth with Prince Charles in 1949 (left), and with her baby daughter Princess Anne in 1950 (right). Anne is wearing the royal christening robe, which is made of Honiton lace.
Princess Elizabeth and the Duke of Edinburgh doing Canadian folk dances during their trip in Ottawa in 1951.
The Queen in 1970 (left), and crowning her son, Prince Charles, as Prince of Wales during the investiture ceremony at Caernarfon Castle (right).
Queen Elizabeth II laughing while taking shelter under an umbrella at the Royal Windsor Horse Show in 1977 (left), and having a cup of tea while in Northern Ireland on a royal visit (right).
Queen Elizabeth II with Prince Charles and his fiancé, Lady Diana Spencer, at Buckingham Palace, in 1981 (right), and the couple kissing on the balcony of Buckingham Palace in London after their marriage.
Queen Elizabeth II inspects the ruins of Windsor Castle with a firefighter following a fire in 1992.
Queen Elizabeth II keeps a close eye on a barn owl that landed close to her as she watched a flying display of birds of prey during a visit to the Royal Windsor Horse Show in 1995 (left), and watches proceedings at the Royal Windsor Horse Show in 1992 (right).
Queen Elizabeth II being shown the gardens being exhibited at the Chelsea Flower Show, London, in 2004 (left), and giving an audience at Buckingham Palace to Tony Blair, the then prime minister (right).
Queen Elizabeth II waves to crowds at Waverley Station before boarding the steam locomotive Union of South Africa on 9 September, 2015, in Edinburgh, Scotland.