However, researchers have dated the film to at least 1929 (although earlier estimates placed its production in 1930). The illegality of hardcore pornographic films in the United States in the 1920s and 1930s means that no producer, performer or other credits for The Surprise of a Knight are identifiable.
Most historians consider the first genuine American stag film to be A Free Ride, produced and released in 1915. However, like most of the films which came after it, Le ménage moderne du Madame Butterfly only shows male-male sex acts as deviant, firmly establishes the heterosexuality of the characters, and usually depicts gay sex acts as essentially bisexual (e.g., male-male sexual contact occurs while the men are also having heterosexual intercourse). By 1920, the first hardcore homosexual sex acts were depicted in the film Le ménage moderne du Madame Butterfly. Hardcore pornographic films (later called 'stag films') first appeared in Europe in 1908.
The first known motion pictures depicting nude men were made by Eadweard Muybridge in the 1880s and 1890s as part of his studies of human locomotion.
