Prince William with his wife Kate and their pageboys and bridesmaids When Kate returns to north Wales with Prince William next week, she will begin married life with the knowledge that whatever roles she takes on, she has one definite responsibility,producing an heir. \"If Kate is not pregnant in the next nine months, she will be defying 200 years of royal tradition,\" said Andrew Morton, a biographer of William\'s late mother Diana who has just written a book about the newlyweds.
After years of waiting for her prince to propose, the 29-year-old will be expected to move quickly to produce an heir for the second-in-line to the throne, to ensure there is no break in the line of succession.
Her predecessors certainly wasted no time, William was born barely 11 months after his mother Diana married his father Prince Charles in 1981.
And Charles himself, the heir to the throne, was born almost exactly a year after his parents Queen Elizabeth II and Prince Philip married in 1947.
Asked about his plans for children in an interview in November to mark his engagement, William said: \"I think we\'ll take it one step at a time. We\'ll sort of get over the marriage first and then maybe look at the kids.
\"But obviously we want a family, so we\'ll have to start thinking about that.\"
Having postponed their honeymoon, William and Kate spent the weekend at an undisclosed location in Britain before beginning married life on the isle of Anglesey in Wales, where the prince is a helicopter search and rescue pilot.
He must serve another two years with the Royal Air Force (RAF) there, ensuring the newlyweds can start married life in rural seclusion.
Reports suggest Kate\'s public engagements will initially be light, a charity gala in London is expected to be one of only a few events before a tour to Canada from June 30 to July 8, the couple\'s first as husband and wife.
\"The most important thing to remember is that he\'s not heir to the throne,\" Paddy Harverson, Prince Charles\' communications secretary, told the BBC.
\"He\'s second in line, and he\'s not a full-time royal, he\'s a full-time pilot working a normal job for the RAF search and rescue.\"
Ever since he started his job in September, William has struck a balance between public engagements and his work, he has not neglected the former but he has worked just as many shifts as his non-royal colleagues.
Despite being the new Duchess of Cambridge, Kate must ready herself for the life of a service wife, where her husband works 24-hour shifts and regularly completes dangerous rescue missions.
But she already has some experience, having spent much of the last few months living with him in Anglesey in the same cottage where they are expected to return.
After graduating with a degree in art history from St Andrews university in Scotland, where she met her husband, Kate worked as an accessories buyer for a fashion chain and then for her parents\' party supplies company.
But her career has been viewed in the media as underwhelming, and she is expected to embrace the charity work that comes with royal life.
Palace aides are said to have given her some time to work out exactly what she wants to do.
\"I really hope I can make a difference, even in the smallest way,\" Kate has said.
Robert Jobson, who has written a book on the couple, reported in the News of the World on Sunday that Kate has told friends she is in no rush to have a baby, saying \"one thing at a time, we want to enjoy being together.\"
Royal historian Hugo Vickers said her duties were clear, however.
\"If I\'m being brutal about it, Catherine\'s duty is to make her husband happy and to produce an heir,\" he said.
William\'s marriage \"makes it possible to have another generation of the House of Windsor in direct line to the throne, a boy who will automatically become king or a girl who might be queen\".
Under the law of succession, the first son Kate has would be next in line to the throne after Prince William. But if they have a girl, her place would be behind any brother she may have.
The British government has indicated it would be open to amending the law to ensure that any of Kate\'s children has a chance at the throne.