In the third book of his Rhetoric (c. 330 BC), Aristotle casually reports an anecdote about a tense moment in the life of Euripides. The anecdote offers a tantalizing glimpse at the imagined intersection between theatre and public life in Athens, but more importantly for us it dramatizes an unusual stance on biographical methodology. According to Aristotle, Euripides was once brought to court in an antidosis case: in democratic Athens, if someone did not have the resources for a liturgy that he had been called upon to perform, he could nominate another, richer citizen for the task. We do not know the details of the antidosis involving Euripides, though evidently a dispute arose as to whether Euripides or his opponent, Hygiaenon, was truly the richer citizen, better equipped to perform the liturgy. Hygiaenon supposedly attempted to discredit Euripides by reminding the jurors of a notorious line that one of the playwright's characters pronounced on the stage. In Euripides’ Hippolytus, after Phaedra's nurse has revealed to Hippolytus her mistress’ desire for him, Hippolytus renounces his earlier promise of secrecy. The nurse entreats him to remember his oath to silence, but Hippolytus replies ‘My tongue swore, but my mind is unsworn’. Hygiaenon supposedly cited this line as evidence of Euripides’ own duplicitous nature, presumably in an attempt to prove that Euripides was the wealthier potential liturgist. But to Hygiaenon's accusation Euripides made his own ready reply, namely that:
αὐτον ἀδικεῖν τὰς ἐκ τοὺ Διονυσιακοῦ ἀγῶνος κρίσεις εἰς τὰ δικαστήρια ἄγοντα· ἐκεῖ γὰρ αὐτῶν δεδωκέναι λόγον, ἢ δώσειν εἰ βούλεται κατηγορεῖν.
[Hygiaenon] was wrong to bring verdicts from the agon at the Dionysia into the courtroom, for [Euripides] had already given an account of those things there, or would give one if [Hygiaenon] should wish to make a charge against him.
Hippolytus had been performed as part of Euripides’ only first prize-winning didascalia, at the Great Dionysia in 428. But for the Euripides of Aristotle's anecdote, that victory or ‘verdict’ was of no relevance to the trial at hand: what happens on stage at the Great Dionysia stays on stage at the Great Dionysia, and a line delivered in the Theatre of Dionysus should not be used against the author sitting in court as an ordinary Athenian citizen.