Earlier today, Kensington Palace confirmed that the Duchess of Cambridge has given birth to a baby boy. And, while we are yet to learn the baby’s name, it has been revealed that his title will be HRH Prince of Cambridge.

This marks the second son for Kate Middleton and her husband, Prince William, following their firstborn, Prince George, in 2013.

Their middle child and only daughter (so far), Princess Charlotte, was born in 2015.

Now, though, a history lesson.

The rule of primogeniture – a feudal dictate by which a hereditary title passed to the eldest son puts male children ahead of their siblings, regardless of their age – is the very same rule that saw Henry VIII become obsessed with bonking every woman in the kingdom in a bid to get himself a son.

Or, to put it more succinctly, it’s where the phrase “an heir and a spare” stemmed from – and, until the introduction of new legislation in 2015, boys were always given priority over their sisters in the line to the throne.

Now, thanks to reform measures known as the Perth Agreement, all royal girl children born after 2011 now hold their place in the line of succession – even if they have younger male siblings. Which means that Charlotte, the country’s youngest princess, will no longer be overlooked because she is “just a girl”. 

Instead, the newborn prince is fifth in line to the throne, after his grandfather Prince Charles, father Prince William and two older siblings.

However, while the monarchy has abolished sexist inheritance laws, it is worth noting that the aristocracy still abides to this centuries-old tradition.

Due to rules dating back through to Normandy times, titles have to pass to and through men. As if that weren’t strict enough, these male heirs must all be legitimate (aka the sons of married parents).

This means that an aristocrat’s eldest daughter cannot inherit her father’s title, but she can be left her fair share of his property and money, if he chooses to do so in his will. Unfortunately, however, the majority of aristocratic fathers tend not to do this. Instead, they prefer to leave their estates to the same man who inherits their title, and this is mostly down to historical tradition (not to mention pressures from their fellow Lords, Earls, Dukes, and so on).

It remains to be seen whether or not the new rules around royal succession will inspire the aristocracy to stop propagating sexism on the grounds of a hallowed tradition. There’s no denying, though, that Princess Charlotte has made history today – and, at just two years old, struck a blow for women everywhere.

Read more: Why it’s time to stamp out Britain’s sexist inheritance rules

Image: Getty