Sir Richard C. Jebb, Commentary on Sophocles: Trachiniae

οὐδὲν ἱστορῶν, compared with the words of Lichas himself (317 “οὐδ᾽ ἀνιστόρουν μακράν”), seems better taken as=‘because he had not been inquiring’ (“ὅτι οὐδὲν ἱστόρει”), than, ‘because he did not know’ (cp. O. T.1484 f.).

Many editors place a comma after ἐφώνει. This implies that δῆθεν could stand as the first word of a sentence or a clause. Now there are certainly instances in which the special point of the irony conveyed by “δῆθεν” lies in words which follow it: yet, even then, “δῆθεν” is also retrospective. Aesch. P. V.986“ἐκερτόμησας δῆθεν ὡς παῖδ᾽ ὄντα με”: here “ὡς παῖδ᾽ ὄντα” is the point: but that is no reason why “δῆθεν” should not refer to the whole sentence: i.e., ‘thou hast mocked me, forsooth, as though I were a child,’ represents the sense no less well than, ‘thou hast mocked me as if, forsooth, I were a child.’ The same remark applies to Thuc.1. 127“τοῦτο δὴ τὸ ἄγος οἱ Λακεδαιμόνιοι ἐκέλευον ἐλαύνειν δῆθεν τοῖς θεοῖς πρῶτον τιμωροῦντες”. Id. 4. 99“οὐδ᾽ αὖ ἐσπένδοντο δῆθεν ὑπὲρ τῆς ἐκείνων”. This last example would really show “δῆθεν” as the first word of a clause, if it were necessary to take it exclusively with “ὑπὲρ τῆς ἐκείνων”: ‘nor, again, were they (the Boeotians) going to make a truce about ground which, forsooth, was Athenian.’ But the sense is rather: ‘nor, again, were they going to make a truce, forsooth, [i.e., as the Athenian proposal implied,] about ground which was Athenian.’ And so, here also, the irony of δῆθεν affects the whole sentence, and not only the words οὐδὲν ἱστορῶν.