tetralogies

Tetralogy is a term used to describe a set of four related works that together form a single narrative, theme, or universe. The word comes from the Greek tetra, meaning four, and -logia, meaning discourse or study. In literature, film, and other media, a tetralogy is designed to present a longer, more interconnected arc than a single work or a trilogy.

In classical Greece, tetralogies were produced as a program at festivals such as the City Dionysia, typically comprising three tragedies and a satyr play performed by the same playwright. The four works were intended to be experienced together as a unified dramatic cycle, though few complete tetralogies survive today; the practice influenced later concepts of long-form storytelling.

In modern usage, tetralogies describe four-part narrative series across media, including novels, comics, and film franchises. They often feature an overarching plot and recurring characters, with the fourth installment serving as conclusion, turning point, or recontextualization of earlier events. Some tetralogies are planned from the outset; others emerge from expanding a successful initial work.

While related concepts include trilogies (three works) and quintets (five works), tetralogies occupy a distinct position in long-form storytelling. The term is sometimes used interchangeably with quadrilogies in contemporary publishing and media discourse.