The newly-born daughter of the Duke and Duchess of Cambridge is the first female to have the same succession rights to the throne that she would have had if she had been born a male.
Until the rules governing Royal succession changed in 2011, she would have been leapfrogged in her position in line by any younger brothers.
The as yet unnamed baby is first girl born to the Royal family to take the title princess for 25 years, and is the highest-ranking female in line to the throne (after Princes Charles, William and George).
The change in the succession rights is the latest adaptation of monarchy to the modern world.
Gradual adaptations over the centuries have been the key to the success of the Royal family, which is one of the few to survive. There are only about 25 such families globally now.
In the earliest surviving Belfast News Letters from 1738 and 1739, which were serialised last year, almost every country was ruled by some form of hereditary head of state. Reports from round the world told of kingdoms and emperors.
You could argue that having female monarchs has been at the heart of the success of the British royalty. Three of the longest serving and most popular inhabitants of the throne were Queens Elizabeth I, Victoria and the present Queen.
Between them these three women have been head of state for an astonishing 172 out of the last 457 years. Only one man in that time has come close in terms of longevity, George III, who reigned for 60 years. His tag, ‘the king who lost America,’ is hardly a fond one.
It is unlikely the concept of royalty would have the overwhelming support it now enjoys in the UK if it was not for the current Queen. Happily for monarchists, the immediate heirs to the throne are popular: Charles and William.
The nation looks forward to getting to know the next generation: George and his younger sister.