, circa 1780–1782 The twice-widowed Fitzherbert soon entered London high society. In spring 1784, she was introduced to a youthful admirer:
George, Prince of Wales, six years her junior. The prince became infatuated with her and pursued her endlessly until she agreed to marry him. Secretly, and – as both parties were well aware – against the law, they went through a form of marriage on 15 December 1785, in the drawing room of her house in Park Street, London. Her uncle, Henry Errington, and her brother, John Smythe, were the witnesses. The marriage ceremony was performed by one of the prince's
Chaplains in Ordinary, the Reverend Robert Burt, whose debts of £500 (£ in ) were paid by the prince to release him from
Fleet Prison. The marriage was not valid under English law because it had not received the prior approval of
King George III and the
Privy Council as required by the
Royal Marriages Act 1772. Had approval been sought, it might not have been granted for many reasons, including, for example, Fitzherbert's Catholic religion. Had consent been given and the marriage been legal, the Prince of Wales would have been automatically removed from the
succession to the British throne under the provisions of the
Bill of Rights and the
Act of Settlement 1701 and replaced as heir-apparent by his brother, the
Duke of York. On 23 June 1794, Fitzherbert was informed by letter that her relationship with the Prince was over. George told his younger brother, the Duke of York, that he and Fitzherbert were "parted, but parted amicably", conveying his intention to marry their first cousin, Duchess
Caroline of Brunswick. During the first few years of his reign as King George IV, he turned violently against Fitzherbert and several former associates. Following the death of George IV on 26 June 1830, it was discovered that he had kept all of Fitzherbert's letters, and steps were taken to destroy them. Fitzherbert told George IV's brother,
King William IV, about their marriage and showed him the document in her possession. He "begged her to accept the title of Duchess, but she refused, asking only permission to wear widow's weeds and to dress her servants in royal livery". ==Death==