Meanwhile the affair still maintained a semi-religious character; the place of presentation was still around the altar of Dionysos and the chorus was retained, taking its part in the action with explanation and comment, still delivered, however, in dithyrambic measure and with accompaniments of rhythmic gesture. The platform of the altar being limited in space, the dialogue was usually confined to two actors at a time, though a third was sometimes allowed. If there were other characters involved, these actors would often “double” the parts; disguising themselves by change of costume, especially by the use of masks. This demanded some kind of a screen behind which the actors could change their costumes and also wait until their presence was required. Skins hung upon poles would at first serve the purpose, or a _skene_ or tent, from which we derive our word scene, might be used. Whichever it were, it would interfere with the view of the action from the back and so draw the audience to the “front.” * * * * * The most important remains of Hellenic theatres are the =Theatre of Dionysos=,[4] cut out of the side of the Acropolis, and the theatre at =Epidauros=, in Argolis, Greece. The plan of the theatre of Dionysos is that of a semi-circle, the ends of which are prolonged for a short distance in a direction at right angles to the front of the skene. Within the horseshoe was the circular orchestra, still whole at =Epidauros=, in which the main action was carried on by actors and chorus. A different plan is given by the Roman architect, Vitruvius. It is to be noted, however, that Vitruvius lived in the reign of Augustus, by which time what was pure Hellenic had become modified by foreign influences into Hellenistic. He relates, for example, that in his time the height of the _logeion_ or speaking platform--the stage of to-day--was from 10 to 12 feet. In earlier times, including probably the period of the Classic drama, the logeion was the platform around the altar, supplemented possibly by a platform two or three feet high extending across the front of the _skene_, from which, at certain points in the play, some, at least, of the actors spoke. This platform, being in front of the scene and enclosed at the sides by projections of the latter, was called the _proskenion_, from which is derived our word proscenium with its different meaning.