The term 'Pictures with Posses' refers to a type of film genre that originated in the early 20th century. Oaters, or 'OATER' films, are a subgenre of this type of film and typically feature Western themes and settings. Oaters typically feature a hero, often a cowboy, who is pitted against a villain or group of villains. The hero is usually accompanied by a posse of other characters, such as cowboys, Native Americans, or lawmen, who help him in his quest. Oaters were popular in the 1930s and 1940s, but have since declined in popularity.