It’s a very formal and fancy-sounding title, but frankly, also sounds like it was plucked out of thin air. And well, it kind of was.
You see, while there was previously a Duke of Sussex before Prince Harry was given the title, there has never been a Duchess of Sussex before Meghan.
Aside from it being a very fitting position for the former American actress who didn’t exactly fit the narrow mould of a British princess, it’s also a title that comes with a fascinating backstory.
The first Duke of Sussex was Prince Augustus Frederick, who was born in 1773, was only given his Dukedom in 1801. The prince was the sixth son (and ninth child) of King George III, who was Queen Victoria’s grandfather.
According to the Royal Collection Trust, Prince Augustus was known for his progressive views, and supported the abolition of the slave trade, the removal of civil restrictions on Jews and Roman Catholics.
So it's not really surprising that he found the Royal Marriages Act of 1772 to be a restrictive piece of legislation he was going to completely ignore.
Instead of asking for permission to marry the lady of his choosing from the monarch of the day (his dad), Prince Augustus married Lady Augusta Murray in secret in 1793.
The pair were living in Rome at the time - and it was a bit easier to keep a secret back then - but still, King George found out and in 1794 declared the marriage void.
This meant that Lady Augusta and Prince Augustus two children, (unoriginally named Augustus and Augusta) were deemed illegitimate and had no hope of inheriting any royal titles their father had.