Duke of Cambridge: A New Title
At 8.00am on Friday 29th April 2011, the day of the royal wedding, Buckingham Palace released a statement to say that The Queen had created her grandson, Prince William of Wales, Duke of Cambridge.
The correct forms of address for William and Kate are now His Royal Highness The Duke of Cambridge, and Her Royal Highness The Duchess of Cambridge. Like all dukedoms (both royal and non-royal) the title also has lesser (or subsidiary) titles, in this case Earl of Strathearn and Baron Carrickfergus, but in all official publications, including the Court Circular, they will simply be known as the Duke and Duchess of Cambridge.
In conferring a dukedom upon her grandson, The Queen was conforming to a long-observed royal tradition. The Queen created her second son, Prince Andrew, Duke of York on his wedding day in 1986, and also created her youngest son, Prince Edward, Earl of Wessex upon his wedding day in 1999. Upon the death of the present Duke of Edinburgh the dukedom will descend to the Prince of Wales - and upon the Prince of Wales's succession to The Throne Prince Edward will be created Duke of Edinburgh).