well the prince you probably mean is not a prince he is just and old ugly man (the uglyest of them all) in the end she doesnt even marry him... although id love to hear that story!
Britta marries the prince at the end of the book.
Catherine, Duchess of Cambridge Formerly Catherine (Kate) Middleton
William and Catherine (Kate) are the Williams family now or if you mean queen Elizabeth's family it is called Windsor
Prince William married to Catherine Middleton in 29 April 2011
On the morning of the Royal Wedding, Queen Elizabeth II granted Prince William with the titles Duke of Cambridge, Earl of Strathearn and Baron of Carrickfergus. Upon her marriage to Prince William, Catherine became the Duchess of Cambridge, Countess of Strathearn and Baroness of Carrickfergus. She DOES NOT become Princess Catherine!!! She becomes Princess William of Wales. When Her Majesty dies and Prince Charles assumes the throne, Prince William (as heir apparent to the throne) will be known as The Prince of Wales (like his father is now), when this happens, Catherine will become The Princess Catherine, Princess of Wales (in the way Diana was).
Prince William and Princess Catherine plan to visit the US in July 2011.
now that she is married to prince william, she will now be called Kate Middleton is now Catherine, Duchess of Cambridge.
At university
Prince William and Catherine were married at Westminister Abbey in England.
A Queen in the UK can be both a female monarch (Queen regnant, such as Elizabeth II) or a Queen consort, who is not a ruler, she is the King's wife.
Catherine Middleton is the wife of Prince William.
Catherine, Duchess of Cambridge