Here are Prince Harry and Meghan Markle's new royal titles, and why she's not a princess

Maria Puente | USA TODAY

Show Caption Hide Caption Harry and Meghan exchange vows Prince Harry and his new bride Meghan Markle exchange vows.

On Saturday morning, she woke up as Meghan Markle, American citizen. By midday Saturday, she was Her Royal Highness Meghan, Duchess of Sussex — still an American but on her way to becoming a new royal citizen of the United Kingdom.

On the morning of Prince Harry and Markle's wedding, his grandmother, Queen Elizabeth II, as expected granted him a new title: HRH Prince Harry, Duke of Sussex. That makes his bride a royal duchess, known formally as HRH Meghan, Duchess of Sussex.

(The queen also bestowed secondary titles, for when they're in Scotland, for instance, of Earl of Dumbarton and Baron Kilkeel.)

Harry, 33, will not be the first Duke of Sussex, although it's been two centuries since the last one. But Meghan, 36, will be the first woman ever to carry the title HRH Duchess of Sussex.

No, she will not be officially known as Princess Meghan, although many people, will call her that. After all, many call the former Kate Middleton "Princess Kate," even though her formal title is HRH Catherine, Duchess of Cambridge.

Why is that? Because the sorting of royal titles is complicated, little understood by titleless Americans and only dimly understood by Brits outside royal and aristocratic circles.

Throw in the exigencies of headline writers — always in search of short, catchy, click-attractive names — and you can see how confusion can reign, no pun intended.

The bottom line is the monarch decides royal titles, based on tradition, personal preference and whether or not a particular title is currently vacant, as it were. It's a tradition that the monarch grants a new title to male members of the royal family on their wedding day. This "gift" is within the monarch's power to grant; the government of the day has nothing to do with it.

But the traditions are different for women. Generally, royal women are called "Princess" before their name if they were born a princess — meaning their parent is royal.

So, for example: HRH Princess Beatrice and HRH Princess Eugenie, Harry's cousins, who are the daughters of HRH Prince Andrew, Duke of York, the queen's second eldest son.

Another example: Princess Anne, the queen's only daughter. Her two children, Peter Phillips and Zara Phillips Tindall, are full members of the royal family but they don't have any titles because Anne opted at their birth not to ask for titles. The same applies to Anne's three grandchildren (with one more on the way).

Sally Bedell Smith, the American royal biographer who understands the protocol about royal titles, says that technically Kate is a princess and soon Meghan will be too because they're married to princes.

"After all, when they signed the birth registration for (newly born) Prince Louis of Cambridge, her occupation was listed as 'Princess of the United Kingdom,' " Smith says. "But the correct form is 'Princess William of Wales' and 'Princess Henry of Wales,' " since their princess status derives from their husbands.

But that's never going to fly, so royal duchess is the agreed-upon title.

But what about Princess Diana, Harry's late mother? Technically, the former Lady Diana Spencer became HRH Diana, Princess of Wales, when she married Harry's father, Prince Charles the Prince of Wales, in 1981, and that is what the palace always called her.

Headline writers had other ideas. She was Princess Diana (or Princess Di) from the start and stayed that way after her divorce (although she lost the HRH) and until her death in a car wreck in Paris in 1997. Britain, like America, has a free press and palace protocol be damned.

So what's the history of the title Duke of Sussex and who was the last to hold it?

Sussex is one of several vacant royal dukedoms (Clarence, Connaught, Windsor, Albany, Cumberland are others), and derives its name from the southeastern county of Sussex (formerly the ancient Anglo-Saxon kingdom of Sussex) on the English Channel coast.

The last royal to hold the title was Prince Augustus Frederick, the sixth son of George III (the king who lost the American colonies), who got it in 1801. Although he was the favorite uncle of Queen Victoria (daughter of one of his elder brothers), Sussex had a scandalous marital history, at least for his era.

He married twice, in secret and illegally: He did not have the required consent of the monarch (his father and later his brother, William IV) as called for by the Royal Marriages Act of 1772 (since altered in 2013 requiring the consent of the monarch for just the first six in line to the throne).

His first marriage, to Lady Augusta Murray in 1793, was annulled a year later although the two continued to live together and had two children. They separated in 1801 just before he got the title. He married a second time, to Lady Cecilia Buggin, in May 1831, again illegally, because he didn't get permission from his elder brother the king.

Because his wives were not legitimately his wives, neither got the title Duchess of Sussex. When the duke died in 1843, he had no legitimate children so the title became extinct.

Until now.