The Queen conferred the dukedom – the highest rank in the British peerage – on her grandson as is customary on the occasion of a royal wedding.
The couple, who met at St Andrews University, were also given a Scottish title and a Northern Irish one.
It had been expected that the prince would become the Duke of Cambridge, but he will hope to avoid the fate of the last holder of the title who became a figure of scandal after marrying a commoner for love.
Buckingham Palace said in a statement published at 8am on Friday: “The Queen has today been pleased to confer a Dukedom on Prince William of Wales.
“His titles will be Duke of Cambridge, Earl of Strathearn and Baron Carrickfergus.
“Prince William thus becomes His Royal Highness The Duke of Cambridge and Miss Catherine Middleton on marriage will become Her Royal Highness The Duchess of Cambridge.”
Experts welcomed the choice of Duke of Cambridge as the prince’s new title.
Charles Kidd, editor of Debrett's Peerage And Baronetage, said: “It has a long royal tradition, and is immediately recognisable as an English title, it's one of those places everyone has heard of."
The Mayor of Cambridge, Sheila Stuart, said: “We have been hoping for this ever since they announced their engagement.
“Cambridge has had some strong royal ties in the past - the Duke of Edinburgh has been chancellor of the university for 34 years.
“It strengthens the already excellent relationship we have with the royal family.”
The dukedom was created in 1664, and was first given to the second son of the Catholic king James II. But the title became extinct four times over the centuries when its holders died without heirs.
Appropriately one earlier Duke of Cambridge, the seventh son of George III, was chancellor of St Andrews University where the newlyweds met a decade ago.
His only son, the last holder of the title, served in the Army and married a commoner, like Prince William.
Prince George, born in 1819, refused to have an arranged marriage as he believed such unions were “doomed to failure”.
But he caused a scandal by marrying an actress with whom he already had two children and going on to have a mistress.
His marriage to Sarah Fairbrother was never formally recognised and so she did not receive the title Duchess of Cambridge, becoming known by the nickname Mrs FitzGeorge.
The Duke, who served in the Crimean War and was promoted to Commander-In-Chief in 1887, kept a mistress, Louisa Beauclerk, for more than 30 years. He died in 1904.
The newlyweds passed by an equestrian statue of the last Duke of Cambridge in Whitehall during the carriage procession following today’s service.
It is customary for members of the Royal family to be offered at least one title by the monarch when they are married.
When the royal wedding was announced last year, it was expected that the second-in-line to the throne would be offered a Dukedom, making his wife a Duchess, and Cambridge was the favourite title. Other possibilities were said to have included the Duke of Clarence and the Duke of Sussex.
If the Prince had turned down the titles, he would have remained HRH Prince William of Wales.
As well as a duchess, his new bride may also be known as HRH Princess William of Wales. She does not have the title Princess Catherine, as she is not a princess in her own right.
The new duke’s father, the Prince of Wales, did not take on any additional titles on his wedding day, but his uncle Prince Andrew became the Duke of York when he married while Prince Edward became the Earl of Wessex.
The couple, who met at St Andrews University, were also given a Scottish title and a Northern Irish one.
It had been expected that the prince would become the Duke of Cambridge, but he will hope to avoid the fate of the last holder of the title who became a figure of scandal after marrying a commoner for love.
Buckingham Palace said in a statement published at 8am on Friday: “The Queen has today been pleased to confer a Dukedom on Prince William of Wales.
“His titles will be Duke of Cambridge, Earl of Strathearn and Baron Carrickfergus.
“Prince William thus becomes His Royal Highness The Duke of Cambridge and Miss Catherine Middleton on marriage will become Her Royal Highness The Duchess of Cambridge.”
Experts welcomed the choice of Duke of Cambridge as the prince’s new title.
Charles Kidd, editor of Debrett's Peerage And Baronetage, said: “It has a long royal tradition, and is immediately recognisable as an English title, it's one of those places everyone has heard of."
The Mayor of Cambridge, Sheila Stuart, said: “We have been hoping for this ever since they announced their engagement.
“Cambridge has had some strong royal ties in the past - the Duke of Edinburgh has been chancellor of the university for 34 years.
“It strengthens the already excellent relationship we have with the royal family.”
The dukedom was created in 1664, and was first given to the second son of the Catholic king James II. But the title became extinct four times over the centuries when its holders died without heirs.
Appropriately one earlier Duke of Cambridge, the seventh son of George III, was chancellor of St Andrews University where the newlyweds met a decade ago.
His only son, the last holder of the title, served in the Army and married a commoner, like Prince William.
Prince George, born in 1819, refused to have an arranged marriage as he believed such unions were “doomed to failure”.
But he caused a scandal by marrying an actress with whom he already had two children and going on to have a mistress.
His marriage to Sarah Fairbrother was never formally recognised and so she did not receive the title Duchess of Cambridge, becoming known by the nickname Mrs FitzGeorge.
The Duke, who served in the Crimean War and was promoted to Commander-In-Chief in 1887, kept a mistress, Louisa Beauclerk, for more than 30 years. He died in 1904.
It is customary for members of the Royal family to be offered at least one title by the monarch when they are married.
When the royal wedding was announced last year, it was expected that the second-in-line to the throne would be offered a Dukedom, making his wife a Duchess, and Cambridge was the favourite title. Other possibilities were said to have included the Duke of Clarence and the Duke of Sussex.
If the Prince had turned down the titles, he would have remained HRH Prince William of Wales.
As well as a duchess, his new bride may also be known as HRH Princess William of Wales. She does not have the title Princess Catherine, as she is not a princess in her own right.
The new duke’s father, the Prince of Wales, did not take on any additional titles on his wedding day, but his uncle Prince Andrew became the Duke of York when he married while Prince Edward became the Earl of Wessex.
