Queen Elizabeth II bestowed upon her young grandson the title of Duke of Sussex, making Markle the Duchess of Sussex.
The news was announced early Saturday morning, with an official Royal Communication release. "The Queen has today been pleased to confer a Dukedom on Prince Henry of Wales. His titles will be Duke of Sussex, Earl of Dumbarton and Baron Kilkeel," the statement explained. "Prince Harry thus becomes His Royal Highness The Duke of Sussex, and Ms. Meghan Markle on marriage will become Her Royal Highness The Duchess of Sussex."
The bestowment follows in suit with the monarchy dispensing such titles upon princes on their wedding day. Prince William and Kate Middleton were named Duke and Duchess of Cambridge when they married in 2011. Also, when the queen's second son, Prince Andrew, married Sarah Ferguson in 1986, they were named Duke and Duchess of York.
The title of Duke is the highest rank of hereditary peerage -- followed by marquess, earl, viscount and baron. The title of Duke was traditionally given to extended family members of the Monarchy, or wealthy, influential landowners.
The first-born son of the King or Queen of England is traditionally named the Duke of Cornwall -- a title currently held by Prince Charles, who is next in line for the throne.
Prince Philip, husband of the queen, is the Duke of Edinburgh. The title was created specifically for Philip by King George the VI in 1947, when Philip and Elizabeth wed.
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As for the title of Duke of Sussex -- which pertains to a rural country in southeast England along the English Channel -- it was only held by one other person, Prince Augustus Frederick, from 1801 to 1843.
While the prince had two sons with his wife, Lady Augusta Murray, their marriage was invalidated according to the Royal Marriages Act 1772 -- as their union was held in secret and was not condoned by his father, King George III.
Having no legitimate heirs to inherit his titles -- which also included the Earl of Inverness and Barron Arklow -- Prince Augustus' titles became extinct when he died.
The title of Earl of Dumbarton had also been extinct since 1749, after being first created for Lord George Douglas in 1675. As for Prince Harry being made Baron Kilkeel, the title refers to a small town in County Down in Northern Ireland.