Following is a timeline of the Queen's life and reign:
April 21, 1926 - Elizabeth is born at 2.40 am at 17 Bruton Street, London, and christened on May 29 that year in the private chapel at Buckingham Palace.
December 11, 1936 - She becomes heir apparent, aged 10, when her uncle Edward VIII abdicates and her father becomes King George VI.
November 20, 1947 - She marries navy lieutenant Philip Mountbatten, a Greek prince, at London's Westminster Abbey.
November 14, 1948 - Eldest son Charles is born.
August 15, 1950 - Daughter Anne is born.
February, 1952 - Princess Elizabeth and her husband Prince Philip set out on a tour of Africa and Asia in place of her ailing father, King George VI.
February 6, 1952 - News of the king's death reaches her in Kenya, meaning she is the first sovereign in more than 200 years to accede to the throne while abroad.
June 2, 1953 - Queen Elizabeth is crowned at Westminster Abbey in the first televised coronation service.
November 24, 1953 - The Queen's first Commonwealth tour begins covering a distance of 43,618 miles (70,196 km).
February 19, 1960 - Second son, Prince Andrew, is born.
March 10, 1964 - Youngest son, Prince Edward, is born.
March, 1970 - During a visit to New Zealand, the Queen introduces the "walkabout", a meet-the-people tactic for royal tours.
1977 - The Queen marks her Silver Jubilee - 25 years as monarch - with a tour of Commonwealth countries and lavish celebrations in Britain.
July 29, 1981 - Prince Charles marries Lady Diana Spencer in a glittering ceremony.
June 21, 1982 - Charles and Diana's first child, Prince William, is born.
September 15, 1984 - Charles and Diana's younger son, Prince Harry, is born.
July 23, 1986 - Prince Andrew marries the high-spirited publishing executive Sarah Ferguson, known as "Fergie". The couple become the Duke and Duchess of York.
May 14-26, 1991 - The Queen tours the United States and becomes the first monarch to address Congress.
1992 - Her 40th year on the throne, which she calls her 'annus horribilis' (horrible year), is marked by marital upsets and public dissent.
March, 19, 1992 - Andrew and Sarah announce separation.
April 13, 1992 - Palace announces Anne and Mark Phillips to divorce.
November 10, 1992 - Windsor Castle is badly damaged by fire.
November 26, 1992 - The Queen agrees to pay income tax.
December 9, 1992 - Charles and Diana announce their separation.
March 20, 1995 - The Queen makes the first address by a British monarch to a South African parliament since 1947.
December 20, 1995 - Buckingham Palace confirms the Queen has written to Charles and Diana urging them to divorce.
August 28, 1996 - Charles and Diana are divorced.
August 31, 1997 - Diana and her millionaire companion Dodi al-Fayed are killed when their car crashes while being chased through Paris by photographers on motorcycles. The queen and the royal family are criticised for their reserved response.
November 20, 1997 - Large crowds greet the Queen and Prince Philip as they mark their golden wedding anniversary. In an unusually frank speech, the Queen acknowledges that monarchies survive only through public support.
February 9, 2002 - The Queen's sister, Princess Margaret, dies aged 71 after a life of glamour and heartbreak.
March 30, 2002 - Queen Elizabeth, the Queen Mother, dies at Windsor Castle aged 101.
June 1-4, 2002 - Four days of nationwide celebrations mark the Queen's Golden Jubilee.
April 9, 2005 - Son and heir Prince Charles marries Camilla Parker Bowles at a civil ceremony in Windsor.
April 29, 2011 - The Queen attends the wedding of Prince William and Kate Middleton.
May 17-20, 2011 - The Queen makes a four-day state visit to Ireland, the first by a British monarch since Ireland won its independence from London in 1921.
June 2-5, 2012 - The diamond jubilee to mark her 60th year on the throne sees four days of celebrations along with a nationwide tour. One million people gather for a pageant on River Thames, and millions more attend street parties.
July 22, 2013 - Prince William's wife Kate gives birth to son Prince George.
June 23-26, 2014 - The Queen embarks on what was her last foreign state visit to Germany.
September 9, 2014 - At 5.30 pm UK time, Elizabeth becomes the nation's longest-reigning monarch, overtaking her great-great-grandmother Queen Victoria.
May 2, 2015 - William and Kate's daughter, Princess Charlotte, is born.
April 21, 2016 - Elizabeth celebrates her 90th birthday, the first British monarch to reach such a milestone.
August 2 , 2017 - Prince Philip bows out of public life after 65 years of supporting his wife.
November 20, 2017 - Elizabeth and Philip celebrate their 70th wedding anniversary with a private party at Windsor Castle.
April 23, 2018 - William and Kate's youngest child, Prince Louis, is born.
May 19, 2018 - Prince Harry marries Meghan Markle, a divorced American actress from Los Angeles, at a star-studded wedding at Windsor Castle.
October 20, 2019 - A family row between William and Harry becomes public, with the younger prince confirming the rumours of a rift.
November 15, 2019 - Prince Andrew gives a disastrous interview to BBC TV in an attempt to draw a line under a sex scandal. Days later he is forced to step down from royal duties over his links to the disgraced US financier Jeffrey Epstein, who was jailed in 2008 for child sex offences.
January 8, 2020 - Harry and Meghan announce they will no longer be working members of the royal family. They move to Los Angeles in March.
April 5, 2020 - The Queen makes only the fifth special televised broadcast of her reign to rally the nation amid the COVID-19 outbreak.
April 9, 2021 - Prince Philip, the Queen's husband of 73 years, dies peacefully aged 99 at Windsor Castle.
October 20, 2021 - The Queen spends a night in hospital for the first time in years for what Buckingham Palace termed "preliminary investigations".
November 30, 2021 - Barbados becomes a republic, meaning the Queen is now the head of state of 15 realms.
Jan. 13, 2022 - Buckingham Palace says Prince Andrew has been stripped of his military links and royal patronages and will no longer be known as His Royal Highness as he defends a US lawsuit brought by Virginia Giuffre who said the royal sexually abused her when she was a teenager.
February 6, 2022 - The Queen marks her 70th year on the throne, using the occasion to give her blessing to Charles' second wife Camilla being called Queen Consort when he becomes king.
February 15, 2022 - Prince Andrew pays an undisclosed sum to settle the US lawsuit, but admits no wrongdoing.
February 20, 2022 - The Queen tests positive for COVID-19 and is said to be suffering from mild cold-like symptoms. She soon returns to official duties.
May 9, 2022 - The Queen pulls out of ceremonial opening of parliament due to mobility problems.
June 2-5, 2022 - Four days of celebration in Britain mark the Queen's Platinum Jubilee. The Queen herself has to withdraw from several events due to "episodic mobility issues" but says she has been "humbled" by the support she has received.
September 6, 2022 - The Queen performs what will be her last public duties, accepting the resignation of Prime Minister Boris Johnson at Balmoral Castle and appointing his replacement Liz Truss - the 15th prime minister of her reign.
September 8, 2022 - Queen Elizabeth II dies at Balmoral, aged 96.
September 11, 2022 - Her coffin is driven to Edinburgh, past tens of thousands of mourners lining the route.
September 13, 2022 - Tens of thousands line the streets of London as the coffin is flown to the capital and driven to Buckingham Palace.
September 14-19, 2022 - The Queen's body lies in state at Westminster Hall. Hundreds of thousands of people queue for hours to file past her coffin.