For hundreds of years, the laws of succession to the British throne have followed male-preference primogeniture –placing all brothers ahead of sisters in line for the crown.
But following the birth of the Duke and Duchess of Cambridge’s third child today, Princess Charlotte made history: the royal toddler will remain fourth-in-line for the throne.
As Brittani Barger explains for Royal Central, while Charlotte is still preceded by her older brother, George, the prince of Cambridge; her father, William, the Duke of Cambridge; and her grandfather, Charles, the Prince of Wales, her newborn brother, whose name has yet to be announced, will not take Charlotte’s place in line for succession.
The young royal owes her thanks to a 2011 agreement among the leaders of the Commonwealth—the 16 countries headed by Elizabeth II—which unanimously agreed that birth order, not gender, would determine the succession of Britain’s forthcoming royal children.
When then-British Prime Minister David Cameron announced the changes, he called the previous rules of succession outdated. “The idea that a younger son should become monarch instead of an elder daughter simply because he is a man… is at odds with the modern countries that we have become,” he said at the time.
The Succession to the Crown Act, subsequently passed by Parliament in 2013, formalized that the succession order would follow absolute – or gender-blind – primogeniture.
The previous English common law tradition stemmed from ancient Norman practice, Sonia Van Gilder Cooke explains for TIME magazine. The rules of succession for the British throne were formalized around the turn of the 18th century as Parliament established the modern United Kingdom. The law stubbornly weathered many modern attempts at reform, until the birth of Prince George in 2013 finally rushed the changes forward, according to the BBC.
Though Elizabeth II declined to state her opinion on the issue of male primogeniture and did not have direct influence upon the 2011 Commonwealth agreement, her court officials report that she privately supports the reform. Writing for the Michigan State Law Review, Christine Alice Corcos, who specializes in gender law in the European Union, speculates that the uncertainty that Elizabeth II experienced as “heiress presumptive” rather than “heiress apparent” might have influenced her support for the rule change – before she took the throne, she could have been displaced if a male heir was born into the family.
As British historian Roger Lockyer tells Cooke, the push for gender equality for royal succession can also be viewed in line with the legacy set by turn-of-the-20th-century royal George V, who realized he had to keep the monarchy relevant with the times to secure its future, something Lockyer terms a “royal survival tactic.”
The modern monarchy has taken its cues from George V. Today, it remains largely popular among Brits, with a 2016 Ipsos Mori poll of British adults conducted ahead of the Queen’s 90th birthday finding that 75 percent believed the “Monarchy has an important role to play in the future of Britain.”
While Princess Charlotte can enjoy her firmly established place in the royal line of succession, she is still out of luck in one regard. While the Succession to the Crown Act of 2013 also replaced the Royal Marriages Act 1772, which forced anyone eligible for the throne to get the ruling monarch’s consent to marry, as one of the first six in line, one day her paramour will still require the Queen’s permission for her hand.