Henrietta Ponsonby, Countess of Bessborough, 1761  1821, born Lady Henrietta Frances Spencer (generally called Harriet), was the wife of Frederick Ponsonby, 3rd Earl of Bessborough and mother of the notorious Lady Caroline Lamb. Her father, John Spencer, 1st Earl Spencer, was a great-grandson of John Churchill, 1st Duke of Marlborough. Her sister was Georgiana Cavendish, Duchess of Devonshire. From The Connoisseur Magazine, published 1902.