a royal prince but as their marriages were invalid under the Royal Marriages Act 1772, they did not become princesses: Maria Anne Fitzherbert, married George, Prince of Wales in 1785 Lady Augusta Murray, married Prince Augustus Frederick, Duke of Sussex in 1793 Lady Cecilia Buggin, married Prince Augustus Frederick, Duke of Sussex. She was later created Duchess of Inverness. Sarah Louisa Fairbrother, married Prince George, Duke of Cambridge in 1847 Although Wallis Simpson married the Duke of Windsor in 1937, and he was a British prince with the style His Royal Highness, having been confirmed as such by letters patent 27 May 1937 from his brother, George VI, Wallis and her descendants from the marriage were expressly denied the style of "Royal Highness" by the same letters patent before she married him. As a duke's wife, she was always styled Her Grace The Duchess of Windsor. Her husband, the Duke of Windsor, insisted that staff and friends should refer to her as Her Royal Highness. There have been two instances where a British princess married a British prince: first The Princess Mary, daughter of George III, who married her first cousin Prince William Frederick, Duke of Gloucester and Edinburgh; secondly Princess Alexandra, Duchess of Fife, granddaughter of Edward VII, who married her first cousin once removed Prince Arthur of Connaught. In the first instance Princess Mary was of higher rank and the Duke of Gloucester and his sister were elevated from the style His/Her Highness to His/Her Royal Highness. In the second instance Princess Alexandra had been granted the style Her Highness by her grandfather the King; as the wife of a Prince she received the style Her Royal Highness. There is also the curious case of Princess Victoria Eugénie of Battenberg, later Queen Victoria Eugenia of Spain (the daughter of Princess Beatrice and Prince Henry of Battenberg). Prior to her marriage to Alfonso XIII of Spain in May 1906, she was styled Her Highness Princess Victoria Eugénie of Battenberg. On 3 April 1906 Edward VII, in order to elevate her standing prior to her wedding, raised her status to Royal Highness per royal declaration which read: "Whitehall April 3, 1906. The KING has been graciously pleased to declare and ordain that His Majesty's niece, Her Highness Princess Victoria Eugenie Julia Ena, daughter of Her Royal Highness the Princess Beatrice Mary Victoria Feodore (Princess Henry of Battenberg), shall henceforth be