The Deipnosophists (1.39)

But Aeschylus was not only the inventor of becoming and dignified dress, which the hierophants and torch-bearers of the sacred festivals imitated; but he also invented many figures in dancing, and taught them to the dancers of the chorus. And Chamæleon states that he first arranged the choruses; not using the ordinary dancing-masters, but himself arranging the figures of the dancers for the chorus; and altogether that he took the whole arrangement of his tragedies on himself. And he himself acted in his own plays very fairly. And accord- ingly, Aristophanes (and we may well trust the comic writers in what they say of the tragedians) represents Aeschylus himself as saying—

I myself taught those dances to the chorus,

Which pleased so much when erst they danced before us.

And again, he says,

I recollect that when I saw ' The Phrygians,' when the men came on who were uniting with Priam in his petition for the ransom of his son, some danced in this way, some in that, all at random.

Telesis, or Telestes, (whichever was his right name,) the dancing-master, invented many figures, and taught men to use the action of their hands, so as to give expression to what they said. Phillis the Delian, a musician, says, that the ancient harp-players moved their countenances but little, but their feet very much, imitating the march of troops or the dancing of a chorus. Accordingly Aristotle says, that Telestes the director of Aeschylus's choruses was so great a master of his art, that in managing the choruses of the Seven Generals against Thebes, he made all the transactions plain by dancing. They say, too, that the old poets, Thespis, Pratinas, Carcinus, and Phrynichus, were called dancing poets, because they not only made their dramas depend upon the dancing of the chorus, but because, besides directing the exhibition of their own plays, they also taught dancing to all who wished to learn. But Aeschylus was often drunk when he wrote his tragedies, if we may trust Chamæleon: and accordingly Sophocles reproached him, saying, that even when he did what was right he did not know that he was ding so.