<Li> Berkeley Square (1933), portrayed by Juliette Compton </Li> <Li> The House in the Square (also titled "I'll Never Forget You" (US) and "Man of Two Worlds") (1951), portrayed by Kathleen Byron </Li> <Li> The Duchess (2008), portrayed by Keira Knightley . The film, directed by Saul Dibb, is based on the biography Georgiana, Duchess of Devonshire by Amanda Foreman . </Li> <Ul> <Li> Emma; Or, The Unfortunate Attachment: A Sentimental Novel (1773) </Li> <Li> The Sylph (1778) </Li> <Li> The Passage of the Mountain of Saint Gothard (1799) </Li> </Ul>

Who is the movie the duchess based on