Elizabeth Christiana Cavendish, Duchess of Devonshire (née Hervey; 13 May 1758 – 30 March 1824) was an English aristocrat and letter writer.

Known as Bess, she was born Elizabeth Christiana Hervey on 13 May 1758, in a small house in Horringer, St Edmundsbury, Suffolk.

She had three brothers, including John, Lord Hervey and Frederick, 1st Marquess of Bristol; and two sisters, Lady Mary Erne and Louisa, Countess of Liverpool.

The marriage was not a success, and the couple separated within five years, after Bess received reports of an "intrigue" between Foster and her maid, Madam Wagniere.

Quin joined the Duchess as her travelling physician in Rome in December 1820, and afterwards attended her in that city during her fatal illness in March 1824.