Passage 10.20.7
εὐθὺς οὖν τῇ ἐπιούσῃ νυκτί, οὐ καθότι ἦν τὰ ἀρχαῖα τῷ ποταμῷ ζεύγματα ἀλλὰ ἐς τὸ κάτω, ὡς μή τις τοῖς Ἕλλησι διαβαινόντων γένοιτο αἴσθησις, καὶ ᾗ μάλιστα ὁ Σπερχειὸς διεχεῖτο ἐς πλέον τοῦ πεδίου καὶ ἕλος τε ἐποίει καὶ λίμνην ἀντὶ βιαίου καὶ στενοῦ ῥεύματος, κατὰ τοῦτο ὁ Βρέννος ὅσον μυρίους τῶν Γαλατῶν ἀπέστειλεν, ὁπόσοι τε νεῖν ἠπίσταντο ἐξ αὐτῶν καὶ ὅστις τῷ μήκει τοῦ σώματος ἐτύγχανεν ὢν ὑπὲρ τοὺς πολλούς· εἰσὶ δὲ καὶ ἄλλως οἱ Κελτοὶ μακρῷ πάντας ὑπερηρκότες μήκει τοὺς ἀνθρώπους.
On the very next night, therefore, Brennus sent about ten thousand Gauls downstream, not by the bridges formerly used over the river, but further down the stream, so that the Greeks might not perceive them crossing. He chose the place where the Spercheius, spreading out over much of the plain, created marshland and a lake instead of flowing with a strong and narrow current. These Gauls included both those among them who knew how to swim and those who happened to exceed most others in bodily height. Indeed, even otherwise the Celts surpass all other men by far in stature.