The Republic by Plato Part 3 Page 34

Very right, he said.

Neither must they represent slaves, male or female, performing the offices of slaves?

They must not.

And surely not bad men, whether cowards or any others, who do the reverse of what we have just been prescribing, who scold or mock or revile one another in drink or out of drink, or who in any other manner sin against themselves and their neighbours in word or deed, as the manner of such is. Neither should they be trained to imitate the action or speech of men or women who are mad or bad; for madness, like vice, is to be known but not to be practised or imitated.

Very true, he replied.

Neither may they imitate smiths or other artificers, or oarsmen, or boatswains, or the like?