Passage 3.8.4
τότε μὲν δὴ τοῦ θεοῦ σείσαντος ὀπίσω τὸ στράτευμα ἀπεχώρησεν ἄχρι Ὀλυμπίας καὶ τοῦ Ἀλφειοῦ προελθόντες· τῷ δὲ ἐφεξῆς ἔτει τήν τε χώραν ἐδῄωσεν ὁ Ἆγις καὶ ἤλασε τῆς λείας τὴν πολλήν. Ξενίας δὲ ἀνὴρ Ἠλεῖος Ἄγιδί τε ἰδίᾳ ξένος καὶ Λακεδαιμονίων τοῦ κοινοῦ πρόξενος ἐπανέστη τῷ δήμῳ σὺν τοῖς τὰ χρήματα ἔχουσι· πρὶν δὲ Ἆγιν καὶ τὸν στρατὸν ἀφῖχθαί σφισιν ἀμύνοντας, Θρασυδαῖος προεστηκὼς τότε τοῦ Ἠλείων δήμου μάχῃ Ξενίαν καὶ τοὺς σὺν αὐτῷ κρατήσας ἐξέβαλεν ἐκ τῆς πόλεως.
At that time, as the god caused an earthquake, the army withdrew back, retreating as far as Olympia and the Alpheios. But in the following year, Agis ravaged the territory and carried off a great part of the spoil. Now a certain Xenias, an Elean, privately a guest-friend to Agis and officially a proxenos to the Spartans, rose up against the popular party along with the wealthy citizens. However, before Agis and his army arrived to their aid, Thrasydaeus, who at that time was leading the people of Elis, defeated Xenias and his companions in battle and expelled them from the city.