Princess Anne is known as the Princess Royal, which has always been a special title in the royal family.
SEE: The Queen’s children unite for deeply emotional vigil - all the photos
Keeping to her promise, she hasn’t left the Queen’s side since Her Majesty passed away aged 96 on Thursday in Balmoral in Scotland.
The Princess Royal has had the honour of accompanying her late mother on her slow journey back to London since she left Balmoral for the last time on Sunday.
WATCH: Princess Anne's last curtsy to the Queen as Her Majesty's coffin arrives in Edinburgh
Also, Princess Anne made history at the Queen’s vigil in Edinburgh by becoming the first female member of the royal family to "stand guard" at the royal mourning tradition known as the Vigil of the Princes.
In military uniform, she stood alongside her brothers – Prince Edward, Prince Andrew and newly appointed King Charles III - at St Giles Cathedral in Edinburgh on Monday.
Now we take a look at why Princess Anne received the special title Princess Royal and what it means…
Why is Princess Anne called Princess Royal and what does it mean?
The Queen bestowed her daughter with the title the Princess Royal in June 1987, a name she will now keep for the rest of her life.
It is typically the title given to the eldest daughter of a reigning monarch and the title is not hereditary.
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Born on August 15 in 1950 in London, Princess Anne has a special place in the royal family as the only daughter of the Queen and The Duke of Edinburgh. She is one of four children and the second child.
At the age of 18, the Princess Royal embarked on public engagements in 1969. Her very first engagement was the opening of an educational and training centre in Shropshire in 1969.
Who in the royal family has had their titles change?
Although Princess Anne’s title is for life, other members of the royal family have seen their titles change since the Queen's death.
Charles now becomes King Charles III and The Duchess of Cornwall will be known as the Queen Consort, reflecting the changes in their roles since the Queen's death.
Prince William and Kate will know be known as the Princess and Princess of Wales. They were formerly known as the Duke and Duchess of Cambridge.
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Also, the children will still be Prince George, Princess Charlotte and Prince Louis but 'of Wales' instead of 'of Cambridge'.
Kate is the first person to receive the title of the Princess of Wales since Princess Diana died.
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