Passage 10.19.7
ἐπὶ μὲν οὖν Θρᾷκας καὶ τὸ ἔθνος τὸ Τριβαλλῶν ἔμελλε Κερέθριος ἡγήσεσθαι· τοῖς δὲ ἐς Παιονίαν ἰοῦσι Βρέννος ἦσαν καὶ Ἀκιχώριος ἄρχοντες· Βόλγιος δὲ ἐπὶ Μακεδόνας τε καὶ Ἰλλυριοὺς ἤλασε, καὶ ἐς ἀγῶνα πρὸς Πτολεμαῖον κατέστη τότε ἔχοντα τὴν Μακεδόνων βασιλείαν. Πτολεμαῖος δὲ ἦν οὗτος ὃς Σέλευκόν τε ἐδολοφόνησε τὸν Ἀντιόχου, καταπεφευγὼς ὅμως ἱκέτης ὡς αὐτόν, καὶ εἶχεν ἐπίκλησιν Κεραυνὸς διὰ τὸ ἄγαν τολμηρόν. καὶ ὁ μὲν αὐτός τε ὁ Πτολεμαῖος ἀπέθανεν ἐν τῇ μάχῃ καὶ τῶν Μακεδόνων ἐγένετο οὐκ ἐλαχίστη φθορά· προελθεῖν δὲ ὡς ἐπὶ τὴν Ἑλλάδα οὐδὲ τότε ἐθάρσησαν οἱ Κελτοί, καὶ ὁ δεύτερος οὕτω στόλος ἐπανῆλθεν ἐς τὴν οἰκείαν.
Now Cerethrius intended to lead an invasion against the Thracians and the tribe of the Triballi; the forces marching towards Paeonia were led by commanders Brennus and Acichorius; and Bolgius attacked the Macedonians and the Illyrians, engaging in battle with Ptolemy, who at that time held the kingship of Macedon. This was the same Ptolemy who had assassinated Seleucus, the son of Antiochus, despite Seleucus having fled to him as a suppliant; this Ptolemy bore the surname Ceraunus ("Thunderbolt") because of his excessive boldness. Now Ptolemy himself died in the combat, and the Macedonians suffered no small disaster. Nevertheless, the Celts did not yet dare to advance upon Greece even at that time, and thus this second expedition returned home.