Final answer:
In the history of theatre, the mediator role has been played by various key figures from playwrights to directors. Classic Greek theatre had playwrights as mediators, which evolved into the formal role of a director with contributions from individuals like Constantin Stanislavski who emphasized psychological realism in acting.
Step-by-step explanation:
The role of the mediator in theatre, historically, has been fulfilled by various individuals in different capacities. The paradigm of the theatre mediator can be seen through key figures such as playwrights, actors, and the evolving role of theatre directors. For instance, in classic Greek theatre, playwrights like Euripides played several roles, setting the stage for the characters' actions, consequences, and the eventual catharsis experienced by the audience. This role evolved into a more formal directorship as shown by the work of Constantin Stanislavski and later, directors in the 19th century.
Throughout history, from the polis of Athens funding festivals to Shakespeare managing and producing his plays, the mediator has been pivotal to theatre. These individuals ensured the plays both educated and entertained society, embodying the Aristotelian belief in the power of theatre to shape minds and character. Figures like Stanislavski further revolutionized acting by emphasizing psychological realism and deep character analysis, thereby mediating the psychological truth from actors to audience.