This Aesop, they tell us, was once acting in a theatre the part of Atreus planning to take vengeance on Thyestes, when one of the assistants suddenly ran across the scene, and the actor, losing control of himself in the intensity of his passion, smote him with his sceptre and laid him dead.
Edition :
Plutarch Lives VII: Demosthenes and Cicero, Alexander and Caesar, ed. E. H. Warmington, trans. Bernadotte Perrin (The Loeb Classical Library 99), Cambridge - London 1967 (first ed. 1919).
Notes :
Cicero wanted to imitate Aesop to become better at convincing others with his speeches - this is an anecdote about the tragedian Aesop