Why Lady Louise's birth was hugely significant for the royal family

It was a joyous occasion for the royal family in November 2003 when the Duke and Duchess of Edinburgh welcomed their first child, Lady Louise.

Their daughter arrived into the world by emergency caesarean section at 11.32pm on Saturday 8 November, weighing 4lbs 9oz. The official announcement read: "Her Royal Highness and her daughter are both stable. As a purely precautionary measure, the baby was taken to the regional neonatal unit at St George's Hospital, Tooting."

But did you know that Louise's birth was hugely significant in the British royal family's history? She was the first royal to be given the surname Mountbatten-Windsor at birth.

The hyphenated name was the brainchild of the late Queen Elizabeth II and her husband Prince Philip. While 'Windsor' had previously been the royal family surname, the late monarch tweaked the moniker to better reflect her marriage to Philip whose surname had been Mountbatten.

In 1960, it was therefore declared in the Privy Council that the late Queen's descendants, other than those with the style of Royal Highness and the title of Prince/Princess, or female descendants who marry, would carry the hyphenated name of Mountbatten-Windsor.

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Louise and her brother James were given HRH titles at birth which they could choose to use when they turned 18, but so far, Louise, now aged 20, has chosen not to do so.

While Lady Louise was the first royal to take on the surname at birth, the new royal surname first appeared on an official document at Princess Anne's wedding to Captain Mark Phillips. Indeed she signed the marriage registrar at Westminster Abbey using the Mountbatten-Windsor surname.

It's been a busy period for Lady Louise, who is currently studying at the University of St Andrews. And the 20-year-old was noticeably absent - for the second year in a row - from the annual Easter Mattins service held at St George's Chapel in Windsor back in March.

While her absence wasn't addressed at the time, it seems likely that Duchess Sophie's daughter had been tied up with her university studies. According to the university's official website, the second semester finished on 8 April, with students enjoying a two-week revision break before commencing exams on 20 April.

Louise's brother James, Earl of Wessex, 16, did make an appearance at the church service, however. For the spring outing, he wore a quirky pale blue tie adorned with white rabbits, while his father, the Duke of Edinburgh, opted for a navy tie emblazoned with bright pink chicks.

Sophie, meanwhile, turned heads in a vibrant purple Prada coat and a cream beret-style fascinator. Renowned for her outfit recycling, the royal mother-of-two first wore the jewel-toned garment on a visit to the String Orchestra at the Royal Artillery Barracks in 2014.