Queen Elizabeth celebrates her 86th birthday on Saturday, the first of two birthdays she will mark this year.
While she was born on April 21, 1926, and generally celebrates the day privately with her family, a further, official sovereign's birthday occurs on a Saturday in June in the United Kingdom, according to the official British Monarchy website.
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Other countries in the Commonwealth choose days on which they want to mark the sovereign's birthday. Canada marks Queen Elizabeth's birthday on the same day it marks Queen Victoria's: the last Monday before May 27.
While she was proclaimed Queen 60 years ago in 1952, after the death of her father, George VI, she is not yet the longest-reigning monarch in British history. That distinction still belongs to Queen Victoria, who ruled for almost 64 years.
Queen Elizabeth's birthday on Saturday is usually marked publicly by gun salutes in central London at midday: a 41-gun salute in Hyde Park, a 21-gun salute in Windsor Great Park and a 62-gun salute at the Tower of London, according to the monarchy website.