The Duke and Duchess of Cambridge have named their daughter Charlotte Elizabeth Diana, Kensington Palace said.
The fourth in line to the throne will be known as Her Royal Highness Princess Charlotte of Cambridge.
She was born on Saturday in the Lindo Wing of London’s St Mary’s Hospital weighing 8lbs 3oz (3.7kg).
Charlotte, the feminine form of Charles, has a long royal pedigree and became popular in the 18th century when it was the name of George III’s queen.
The King bought Buckingham House in 1761 for his wife Queen Charlotte to use as a family home close to St James’s Palace - it became known as the Queen’s House and is now Buckingham Palace.
Earlier in the day gun salutes took place in London to mark the birth.
Soldiers from The King’s Troop Royal Horse Artillery rode out in a procession from Wellington Barracks, near Buckingham Palace, to sound 41 shots in Hyde Park.
At the same time, the Honourable Artillery Company left their Armoury House barracks in the City of London to fire a 62-gun salute at the Tower of London.
