Prometheus Unbound, first published by Shelley in 1820, is a lyrical drama, incorporating elements of lyrical poetry within traditional dramatic structure. This structure is particularly suited to Shelley's goal of retelling the story of Prometheus, inspired by the original work of fifth-century Greek tragedian Aeschylus. The original play was discovered in fragments, recovered, and interpreted by later authors like Shelley.
In the spirit of Aeschylus, many traditional elements of Greek tragedy are featured in Prometheus Unbound, including the chorus (in Act 1, Prometheus's voices from the mountain, spring, etc.). Unlike later, modern plays, Shelley maintains certain traditional stylistic elements of the genre. For instance, Prometheus himself rarely talks in rhymed verse, but both the chorus as well as characters who serve a "choral role" will often speak in rhyming couplets. These variations in the rhyme scheme and metrical structure of characters' dialogue are used in many dramas that predate Prometheus Unbound, including much of Shakespeare's literary catalogue.
Unlike the Greek and Elizabethan plays it takes inspiration from, Prometheus Unbound is a "closet play": Shelley never intended to see it performed live. Thus, the formal elements one typically considers with dramas intended for live performance (stage directions, line delivery, staging, etc.) do not apply.
