The Duchess of Devonshire

Georgiana Cavendish, Duchess of Devonshire (7 June 1757 – 30 March 1806) was the first wife of William Cavendish, 5th Duke of Devonshire, and mother of the 6th Duke of Devonshire.

Her father, John Spencer, 1st Earl Spencer, was a great-grandson of John Churchill, 1st Duke of Marlborough. Her niece was Lady Caroline Lamb. She was the great-great-great-great-aunt of Diana, Princess of Wales.

She attained a large amount of fame in her lifetime. She became notorious for her marital arrangements, her catastrophic love affairs, and her love of gambling; she was famous for her beauty and her political campaigning; and she was a leader of fashionable style.

Lady Georgiana Spencer married the Duke of Devonshire on her seventeenth birthday, 7 June 1774 at Wimbledon Parish Church. He was one of the period's most eligible bachelors.

She had a number of miscarriages before giving birth to four children: three with her husband, and an illegitimate daughter fathered by Charles Grey, 2nd Earl Grey. She also raised the Duke's illegitimate daughter, Charlotte, who was conceived with a mistress.

The Duchess of Devonshire was a celebrated beauty and socialite who gathered around her a large salon of literary and political figures. She was connected to key figures of the age such as the Prince of Wales and Marie Antoinette.

She was an active political campaigner in an age when women's suffrage was still more than a century away. The Spencers and the Cavendishes were Whigs. The Duchess of Devonshire campaigned for the Whigs—particularly for a distant cousin, Charles James Fox—at a time when the King (George III) and his ministers had a direct influence over the House of Commons, principally through their power of patronage. 

The Duchess was haunted by debt all her life. Her addiction to gambling and the extravagent parties were pleasure and her bane. She borrowed heavily from her friends, and used her influence to borrow more from such people as Thomas Coutts of Coutts bank. She borrowed money on the tacit agreement that she would introduce Coutts' daughter's into society. On her death she left a note to her son to pleading that he should make sure the Duke honoured her debts which amounted to almost 20 thousand pounds.

One other scandal accompanies the Duchess. She had one known affair, with the Charles Grey later 2nd Earl Grey. Their was one child from this union, Eliza Couteney, who was brought up by the 1st Earl Grey as Charles' sister.

Information from http://www.amanda-foreman.com/new-yorker.shtml