Passage 10.15.2
ὁ δὲ Ἀπόλλων οὗτος καλεῖται μὲν ὑπὸ Δελφῶν Σιτάλκας, μέγεθος δὲ πέντε πηχῶν καὶ τριάκοντά ἐστι. στρατηγοὶ δὲ οἱ πολλοὶ καὶ Ἀρτέμιδος, τὸ δὲ Ἀθηνᾶς, δύο τε Ἀπόλλωνος ἀγάλματα ἔστιν Αἰτωλῶν, ἡνίκα σφίσιν ἐξειργάσθη τὰ ἐς Γαλάτας. στρατιὰν δὲ τὴν Κελτῶν, ὡς ἐκ τῆς Εὐρώπης διαβήσοιτο ἐς τὴν Ἀσίαν ἐπʼ ὀλέθρῳ τῶν πόλεων, Φαεννὶς προεδήλωσεν ἐν τοῖς χρησμοῖς γενεᾷ πρότερον ἢ ἐπράχθη τὸ ἔργον·
This Apollo is called by the Delphians "Sitalkas," and is thirty-five cubits in height. Most of the statues dedicated by commanders depict Artemis; there is also one of Athena, and two statues of Apollo were set up by the Aetolians after their victory over the Gauls. In fact, Phaennis had foretold in her oracles, a whole generation before the event actually occurred, that the Celtic army would cross from Europe into Asia to bring destruction upon the cities.