LONDON - Prince William and his wife Kate's daughter Charlotte is only the fourth baby born with the title of British princess since the start of World War II.
In the meantime there have been nine British princes born.
Charlotte is the first baby born with the title of British princess since Eugenie, the younger daughter of Queen Elizabeth II's second son Prince Andrew, 25 years ago.
She would have been called Lady Charlotte Mountbatten-Windsor, had not the Queen changed the rules relating to the children of the eldest son of the heir to the throne.
Previously, only the eldest son of the eldest son of the Prince of Wales - ie Prince George - would be born a prince, with the title of a royal highness.
However, the 2012 rule change meant all William's children would be princes or princesses.
Besides Queen Elizabeth, here are the five living females born British princesses: 1936 - PRINCESS ALEXANDRA A princess by virtue of being a male-line grand-daughter of King George V, Alexandra carries out royal duties on behalf of her first cousin Queen Elizabeth.
Born sixth in line to the throne, Charlotte's arrival makes her 49th. Her wedding to Angus Ogilvy in 1963 was watched by an estimated 200 million people on television.
1950 - PRINCESS ANNE Queen Elizabeth's no-nonsense daughter is by repute the hardest-working royal.
She is president or patron of some 340 organisations.
The first British royal to compete in the Olympics, at Montreal in 1976, the equestrian won the 1971 European eventing championship.
She is called the Princess Royal, a title given to the eldest daughter of the sovereign - something Charlotte should one day possess.
Charlotte's birth makes Anne 12th in line to the throne.
1988 - PRINCESS BEATRICE Born fifth in line, the history graduate is the eldest daughter of Queen Elizabeth's second son Prince Andrew.
Beatrice carries out few royal duties and has worked at Sony Pictures.
The first royal to complete the London Marathon, she was also the first to act in a film, appearing as a non-speaking extra in "The Young Victoria" (2009).
The new baby means she drops out of the first six in line to the throne, so no longer has to ask for Queen Elizabeth's permission to marry.
1990 - PRINCESS EUGENIE Andrew's younger daughter had back surgery to correct scoliosis aged 12 and is now an appeal patron for the Royal National Orthopaedic Hospital which treated her.
She graduated in English literature, politics and art history. Like her sister Beatrice, her royal duties are scarce.
She is pursuing a career in the art world and works in New York as a benefit auctions manager.
2015 - PRINCESS CHARLOTTE Fourth in line to the throne, Charlotte is the highest female in the line of succession. New laws mean she cannot be overtaken by younger brothers.
Like her one-year-old sibling Prince George, she will probably be rarely seen in her early years, though a lifetime of royal duties awaits in adulthood.