How did Aeschylus change Greek drama by adding a second actor?

Before Aeschylus, Greek drama was limited to a single actor—the protagonist—who could only engage in dialogue with the chorus.1

By introducing a second actor, known as the deuteragonist, Aeschylus fundamentally transformed the medium. This innovation allowed the two actors to converse with one another, which vastly increased the possibilities for dramatic tension and dialogue. Furthermore, this change provided greater freedom in plot construction and allowed Aeschylus to reduce the role of the chorus, effectively making the plot the leading element of the play. These formal advancements helped shift Greek drama toward a more artistic and intellectual form, laying the foundation for the aesthetics of Western theatre.12