Passage 4.16.7
ἀφικόμενος καὶ ὥς οἱ προσέταξεν ἡ Πυθία καταβὰς ἐς τὸ ἄδυτον ἱερὸν τοῦ Τροφωνίου τὸ ἐν Λεβαδείᾳ. ὕστερον δὲ τὴν ἀσπίδα ἀνέθηκεν ἐς Λεβάδειαν φέρων, ᾗ δὴ καὶ αὐτὸς εἶδον ἀνακειμένην· ἐπίθημα δέ ἐστιν αὐτῆς ἀετὸς τὰ πτερὰ ἑκατέρωθεν ἐκτετακὼς ἐς ἄκραν τὴν ἴτυν. τότε δὲ Ἀριστομένης ὡς ἐπανῆκεν ἐκ Βοιωτίας εὑρών τε παρὰ τῷ Τροφωνίῳ καὶ κομισάμενος τὴν ἀσπίδα, αὐτίκα ἔργων μειζόνων ἥπτετο.
Having arrived, he descended, according to the command given him by the Pythian oracle, into the sacred sanctuary of Trophonius at Lebadeia. Later, he dedicated his shield at Lebadeia, bringing it himself, and I have personally seen it placed there. Upon it is fitted an eagle, stretching out its wings on either side towards the upper rim. Then Aristomenes, when he returned from Boeotia after recovering his shield from Trophonius, immediately undertook even greater deeds.