John Loder was established as a British film actor in Germany and Britain before migrating to the United States in 1928 for work in the new talkies. He worked in Hollywood for two periods, becoming an American citizen in 1947. After living also in Argentina, he became a naturalized British citizen in 1959.

Doctor Syn is a 1937 British black-and-white historical dramatic adventure film, directed by Roy William Neill for Gainsborough Pictures. It stars George Arliss, Margaret Lockwood, Graham Moffatt, and Ronald Shiner. The film is based on the Doctor Syn novels of Russell Thorndike, set in 18th century Kent. The character of Syn and the events at the film's climax were both softened considerably in comparison to Thorndike's original storyline.