But why was the monarch's late husband, the Duke of Edinburgh, not given the title of King Consort when his wife became Queen in 1952?
The title King Consort is very rarely used, and this is because most monarchies do not have formal rules on the styling of the husband of a female monarch. The title of King is therefore only given to a royal who inherits the throne and can reign - including Prince Charles, the Duke of Cambridge and Prince George.
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Queen Victoria wanted her husband, Albert, to be granted the title of King Consort, but this was ruled out by prime minister Lord Melbourne. Albert was formally granted the title of Prince Consort 17 years later in 1857.
But unlike Prince Albert, Prince Philip rejected the offer of being officially known as Prince Consort. Instead, a Letters Patent was issued in 1957 giving the Duke the style and titular dignity of a Prince of the United Kingdom of Great Britain and Northern Ireland.
In contrast, all female consorts have the right to be styled as Queen Consort, as wives usually share her spouse's social rank and status. However, she does not formally share the monarch's political and military powers, unless she is acting as regent.
The Queen's mother became Queen Elizabeth when George VI became King in 1936. But when her husband died in 1952 and her daughter Princess Elizabeth ascended the throne, she became known as the Queen Mother to avoid confusion.
Prince Philip pays homage to the Queen at her 1953 coronation
It was previously stated by Clarence House that the Duchess of Cornwall would be styled as Princess Consort when Charles ascends the throne. However, by 2018, all references to this had been removed by Clarence House and Buckingham Palace on their websites.
In her statement released ahead of her accession day, the Queen said: "I remain eternally grateful for, and humbled by, the loyalty and affection that you continue to give me. And when, in the fullness of time, my son Charles becomes King, I know you will give him and his wife Camilla the same support that you have given me; and it is my sincere wish that, when that time comes, Camilla will be known as Queen Consort as she continues her own loyal service."
It is expected that the Duchess of Cambridge will also be known as Queen Consort when Prince William becomes King.
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