Lady Mary Fox Lady Mary Fox Lady Mary Fox (née FitzClarence; 19 December 1798 – 13 July 1864) was an illegitimate daughter of King William IV of the United Kingdom by his mistress Dorothea Jordan. In later life she became a writer. Mary FitzClarence was born in Bushy House as the fourth child and second daughter of the then Prince William, Duke of Clarence, and his companion Dorothea Jordan. She was "a fine looking, brown girl with a pleasant countenance and manners". In 1820, her younger sister Elizabeth was courted by Charles Richard Fox, the eldest but illegitimate son of Lord and Lady
Sophia Dorothea of Celle Duke of Brunswick-Lüneburg by his long-term mistress, Eleonore d'Esmier d'Olbreuse (1639–1722), Countess of Williamsburg, a Huguenot lady, the daughter of Alexander II d'Esmiers, Marquess of Olbreuse. George William eventually married Eleonore officially in 1676 (they had been married morganatically previously). There was some talk of marriage between Sophia Dorothea and the (then) future king of Denmark, but the reigning queen was talked out of it by Sophia of Hanover (her future mother-in-law). Another engagement, to the Duke of Brunswick-Wolfenbüttel, was broken off after Duchess Sophia convinced her brother-in-law of the advantage of having Sophia Dorothea marry her cousin. This occurred