In tragedy, whose subject was usually legend, but which also dealt with questions of the day, such as the occupation of Miletus and the wars with the Persians, there was at first a distinct preponderance of the lyric element supplied by the chorus over the purely dramatic part. Before the time of Aeschylus there was little idea of dramatic treatment; at that time there was only a single actor who, together with the chorus, supplied the whole action, and confined himself chiefly to recitations, so that there could be no question of striking situations and dialogue. Aeschylus then introduced a second actor; and as these actors, by a change of dress, could undertake several parts, the action was enlarged and animated, and the dialogue grew more interesting. When Sophocles added a third actor--an innovation of which Aeschylus, too, made use in his later period, and which constituted the highest number ever used in the Greek drama--the victory of the dramatic part over the lyric was accomplished; and from that time onward the chorus sank in importance compared with the actors, and at last disappeared altogether. In the tragedies of Euripides the dramatic element had become so important that the chorus could really be dispensed with; true, Euripides could not venture entirely to discard this custom, which was sanctified by religion and tradition, but, by gradually diminishing the share of the chorus in the action, he prepared for its complete abandonment. In Aeschylus, therefore, the solemn songs and reflections of the chorus occupy a considerable space, and the chorus even sometimes takes an active part in the action, since it preponderates in the play, and may be regarded as an acting personage; in Euripides its presence is more accidental--it expounds the dogmas and opinions of the poet, but takes no part in the action, and in tragedies it might be entirely left out without injury. In Sophocles alone the chorus and dialogue are harmoniously balanced. Corresponding to these changes in the position of the chorus was the amount assigned to them for declamation. We may say in general that the chorus sang an entrance song (πάροδος), and afterwards during the further course of the play choric songs to mark pauses in the action, accompanied by marching, but without leaving the orchestra, and these were called standing songs (στάσιμα); these long odes divided the drama into a series of parts, called episodes (ἐπεισόδια), which may be compared to our acts, since the action stops during the song, and the spectator has time to collect himself and to let what he has heard and seen act upon him, while the song continued through the interval helps him to keep the impression produced by the action, or else prepares him for what is to follow.