The mistresses of the Prince Regent and his brothers were as well known as the men. The Duke of Clarence, for example, sired ten children with Mrs Jordan, and the Duke of York’s relationship with Mary Anne Clarke caused a major scandal over army commissions. The Duke of Cumberland had rumors of incest, which followed him about. Most of the by-blows sired by upper class families were given the family surname and brought up in the same household as were the legitimate heirs. Occasionally, to avoid scandal, the child was born abroad and at an appropriate age reappeared in England to find a generous “Godfather.”
Maria Fagniani was one such child. She was the daughter of the Marchesa Fagniani, a woman known for bestowing her favors on a variety of gentlemen. Three men claimed Maria as his child. The first of those was the Marchese. The others included Lord March (later the Duke of Queensberry) and George Selwyn. Selwyn left Maria £20,000 pounds as an inheritance. The Duke left her £100,000. At age one and twenty, Mie-Mie married Lord Yarmouth, a man whose reputation was as rakish as her fathers.
Maria Emilia Fagnani (24 August 1771 – 2 March 1856) was the Marchioness of Hertford.
Maria was illegitimate. Born in the 1770s, most likely, she was the daughter of Costanza Brusati, the Italian Marchesa Fagnani, and of either -
- William Douglas, 4th Duke of Queensberry(1724–1810), who was famously detested by Robert Burns.
- George Selwyn (1719–1791), a prominent Tory and lover of Grace Elliott. He was also a member of the Satanic Hellfire Club.
- George Selwyn’s butler.
- Marchese Fagniani
Each of these men believed himself to be her father and left her very large legacies.
On 18 May 1798, Maria married Francis Seymour-Conway, Earl of Yarmouth (1777–1842), the son of the Second Marquess and Isabella Ingram-Shepheard. The Marchioness was the daughter of the Viscount Irvine, and the mistress of the Prince of Wales.
By 1802 they were estranged, and she lived in Paris for the rest of her life. Their children included:
- Lady Francis Maria Seymour-Conway (d. 1822)
- Captain Richard Seymour-Conway, 4th Marquess of Hertford (1800–1870)
- Lord Henry Seymour-Conway (1805–1859)
When George III was insane, he announced that he was going to take Lady Yarmouth as his mistress.
Later, the Marquess inherited his title in 1822. He died in 1842. The dowager Marchioness died in 1856 in Paris.