An ensemble cast or main cast is made up of cast members in which the principal actors and performers are assigned roughly equal amounts of importance and screen time in a dramatic production.
The structure of an ensemble cast contrasts with the popular Hollywood centralization of a sole protagonist, as the ensemble leans more towards a sense of "collectivity and community".
Ensemble casts in film were introduced as early as September 1916, with D. W. Griffith's silent epic film Intolerance, featuring four separate though parallel plots. The film follows the lives of several characters over hundreds of years, across different cultures and time periods. The unification of different plot lines and character arcs is a key characteristic of ensemble casting in film; whether it's a location, event, or an overarching theme that ties the film and characters together.
Films that feature ensembles tend to emphasize the interconnectivity of the characters, even when the characters are strangers to one another. The interconnectivity is often shown to the audience through examples of the "six degrees of separation" theory, and allows them to navigate through plot lines using cognitive mapping. Examples of this method, where the six degrees of separation is evident in films with an ensemble cast, are in productions such as Babel, Love, Actually and Crash, which all have strong underlying themes interwoven within the plots that unify each film.
Other forms of narrative for films with ensemble casts having more or less equal amounts of screen time is demonstrated in recent productions such as The Avengers, where the cast and their characters have already been established in individual films prior to its release. In The Avengers, there is no need for a protagonist in the feature as each character shares equal importance in the narrative, successfully balancing the ensemble cast. Referential acting is a key factor in executing this balance, as ensemble cast members "play off each other rather than off reality".