The state funded it and awarded prizes to the winners. The language was spoken and sung verse, the performance area included a circular floor or orchestra where the chorus could dance, a space for actors (three speaking actors in Euripides' time), a backdrop or skene and some special effects: an ekkyklema (used to bring the skene's "indoors" outdoors) and a mechane (used to lift actors in the air, as in deus ex machina). With the introduction of the third actor (an innovation attributed to Sophocles), acting also began to be regarded as a skill to be rewarded with prizes, requiring a long apprenticeship in the chorus. Euripides and other playwrights accordingly composed more and more arias for accomplished actors to sing and this tendency becomes more marked in his later plays: tragedy was a "living and ever-changing genre" (other changes in his work are touched on in the previous section and in Chronology; a list of his plays is given in Extant plays below). The comic poet, Aristophanes, is the earliest known critic to characterize Euripides as a spokesman for destructive, new ideas, associated with declining standards in both society and tragedy (see Reception for more). However, 5th century tragedy was a social gathering for "carrying out quite publicly the maintenance and development of mental infrastructure" and it offered spectators a "platform for an utterly unique form of institutionalized discussion". A dramatist's role was not just to entertain but also to educate his fellow citizenshe was expected to have a message. Traditional myth provided the subject matter but the dramatist was meant to be innovative so as to sustain interest, which led to novel characterization of heroic figures and to use of the mythical past to talk about present issues. The difference between Euripides and his older colleagues was one of degree: his characters talked about the present more controversially and more pointedly than did those of Aeschylus and Sophocles, sometimes even challenging the democratic order. Thus, for example, Odysseus is represented in "Hecuba" (lines 131–32) as "agile-minded, sweet-talking, demos-pleasing" i.e., a type of the war-time demagogues that were active in Athens during the Peloponnesian War. Speakers in the plays of Aeschylus and Sophocles sometimes distinguished between slaves who are servile by nature and those who are slaves by mere circumstance but Euripides' speakers go further, positing an individual's mental rather than social or physical condition as the true index of worth.