of contradiction. The live-action theatrical films, the 2008 The Clone Wars TV series and its debut film, and statements by Lucas himself were at the top of this hierarchy; such works invariably superseded EU material in case of contradiction. The EU itself was further divided into several descending levels of continuity. After Disney's acquisition of the franchise, Lucasfilm designated all Expanded Universe material published prior to 25 April 2014 (other than the first six theatrical films and the 2008 The Clone Wars film and TV series) as the non-canonical "Legends" continuity. Material released since this announcement is a separate canonical timeline from the original George Lucas Canon, with all narrative development overseen by the Lucasfilm Story Group. The makers of Doctor Who have generally avoided making pronouncements about canonicity, with Russell T Davies explaining that he does not think about the concept for the Doctor Who television series or its spin-offs. Additional works Other writers The canon status of some works by the original writer but not the same publisher, such as "The Field Bazaar", may be debated. This is because copyright used to be exercised by the publisher of the work of literature rather than the author. Campaigning by Victor Hugo led to the Berne Convention which introduced author's rights. However, sometimes in literature, original writers have not approved works as canon, but original publishers or literary estates of original writers posthumously approve subsequent works as canon, such as The Royal Book of Oz (1921) (by original publisher), Porto Bello Gold (1924) (by estate), and Heidi Grows Up (1938) (by estate). Late 20th century In film and television this is common that the original writer does not decide canon. In literature, the estate of H. G. Wells authorised sequels by Stephen Baxter, The Massacre of Mankind (2017) and The Time Ships (1995). Scarlett was a 1991 sequel to Gone with the Wind authorised by the estate. 21st century In 2010, the Conan Doyle estate authorised Young Sherlock Holmes and The House of Silk. Sequels to the stories by P G Wodehouse about the butler Jeeves were sanctioned by Wodehouse's estate for Jeeves and the Wedding Bells (2013) by Sebastian Faulks and Jeeves and the King of Clubs (2018) by Ben Schott. The Monogram Murders (2014) by Sophie Hannah is a sequel to Hercule Poirot novels authorised by the Agatha Christie estate. Fanon Fan fiction is almost never regarded as