With the arrival of the Duke and Duchess of Cambridge's firstborn here are some of the more unusual facts about royal babies.
Royal births are traditionally celebrated with a 41-gun salute, fired as a sign of respect or welcome. In London military saluting stations are in Hyde Park and at the Tower of London. When the Duke of Cambridge was born the Royal Horse Artillery fired a 41-gun salute in Hyde Park to celebrate his arrival.
The Home Secretary was once required to attend the birth of a royal baby to ensure no illegitimate newborns were smuggled in. The custom was abandoned in 1948 when Prince Charles was born as it was decided the practice was “neither a statutory requirement nor a constitutional necessity”.
A notice to announce that a new heir to the throne has been born is placed on an easel in the forecourt of Buckingham Palace. This custom is still followed - even in the age of mass media, when births are also announced on the royal website.
It used to be common for babies to be brought into the world in private or royal residences. The Queen was born at 17 Bruton Street, the London home of her maternal grandparents. The Prince of Wales, Duke of York and Earl of Wessex were all born at Buckingham Palace, while their sister, the Princess Royal, was born at Clarence House. However both the Duke of Cambridge and Prince Harry were born at St Mary's Hospital, Paddington.
The names given to royal babies are not usually revealed straight away and the public is often left guessing for several days. When Princess Beatrice was born in 1988, it was two weeks before her name was known. When William was born in 1982, his parents the Prince and Princess of Wales waited seven days before deciding upon and announcing his name. The Prince of Wales's name, however, remained a mystery for an entire month and was only declared ahead of his christening in the Music Room of Buckingham Palace in December 1948.
Royal babies are often given three or four forenames, which traditionally honour relatives. The Duke of Cambridge was christened Prince William Arthur Philip Louis, while his father was named Prince Charles Philip Arthur George.
Members of the royal family entitled to the title HRH Prince or Princess do not need a surname. However, if at any time a surname is required, such as for marriage, Mountbatten-Windsor is adopted.
Royal births are registered in the normal way, although the Home Secretary is required to notify certain officials including the Lord Mayor of London, the Governors of Northern Ireland, the Channel Islands and the Isle of Man. The Queen's top aide, her Private Secretary Sir Christopher Geidt, informs Governor Generals overseas. Town criers will also sound out the news of the birth of the future monarch.
George V decreed in 1917 that the titles HRH Prince or Princess should be restricted to the children of the sovereign, the children of the sovereign's sons, and the eldest son of the eldest son of the Prince of Wales. However earlier this year the Queen declared that if the Duke and Duchess of Cambridge have a daughter she will be titled Princess. A formal announcement published in the London Gazette read: "The Queen has been pleased by Letters Patent under the Great Seal of the Realm dated 31 December 2012 to declare that all the children of the eldest son of the Prince of Wales should have and enjoy the style, title and attribute of royal highness with the titular dignity of Prince or Princess prefixed to their Christian names or with such other titles of honour."
When William was born he was Prince William of Wales and his children will use Cambridge in the same way, becoming HRH Prince (forename) of Cambridge or HRH Princess (forename) of Cambridge.
Even royal babies have nicknames. Prince William inherited the name Wombat during a trip to Australia, aged two, while his grandmother was affectionately known as Lilibet as a child.
Traditionally, royal christenings are private affairs, held behind closed doors when the baby is just a few months old and attended only by family, godparents and close friends. A family photograph of the baby in its robe is released to the media. Royal children are mostly christened by the Archbishop of Canterbury, in the past often in the Music Room at Buckingham Palace where William's ceremony was held. Prince Harry was christened in St George's Chapel at Windsor Castle.
Royal babies are christened in a replica of the intricate lace and satin christening gown made for Queen Victoria's eldest daughter in 1841. The Earl and Countess of Wessex's son Viscount Severn became the first royal baby to wear the new robe at his christening in 2008. It was made by the Queen's dresser Angela Kelly and the team of dressmakers at Buckingham Palace, and features the same lengthy skirt and elaborate collars and bow as its predecessor.
Royal babies usually have five or six godparents, although the Prince of Wales had eight. Contenders for the role for William and Kate's baby are expected to include the baby's uncles Prince Harry and James Middleton and aunt Pippa Middleton, as well as close friends of the couple such as William's old school friend Thomas van Straubenzee or perhaps one of the van Cutsem brothers. Godparents often also have close historic ties to the royal family.
Silver Cross have been supplying prams for royal babies since 1926, when the Queen was born. The supplier, which has since been given royal approval, has also provided prams for the Prince of Wales, Duke of Cambridge and Prince Harry. Its latest pram, the Silver Cross Surf, Aston Martin Edition, is being sold for £2,000.
The last time a serving monarch met a great-grandchild born in such direct succession to the throne was nearly 120 years ago. Queen Victoria was still sovereign when Edward VIII was born third in line in 1894. The Duke and Duchess of Cambridge's baby will be third in line to the throne behind Prince Charles and Prince William.
Savannah Phillips, the daughter of Peter and Autumn, was the Queen's first great-grandchild. The two-year-old now has a little sister, Isla, meaning the Duke and Duchess of Cambridge's baby is the Queen's third great-grandchild.
Planned changes to succession rules mean it is the first royal baby to be born with an equal claim to the throne regardless of whether it is a boy or a girl. Under the ancient rules of male primogeniture, first born royal daughters in direct line to the throne were leapfrogged by their younger male siblings.