Aeschylus' Prometheus Bound and the Seven Against Thebes

It is not known how many plays the poet wrote, but only seven have been preserved to us. That these tragedies contain much that is undramatic is undoubtedly true, but it must be remembered that at the time he wrote, Æschylus found the drama in a very primitive state. The persons represented consisted of but a single actor, who related some narrative of mythological or legendary interest, and a chorus, who relieved the monotony of such a performance by the interspersing of a few songs and dances. To Æschylus belongs the credit of creating the dialogue in the Greek drama by the introduction of a second actor.