Passage 3.4.5
Δημάρατος μὲν δὴ κατὰ ἔχθος τὸ Κλεομένους καὶ οὐ σὺν τῷ δικαίῳ βασιλείας ἐπαύθη, Κλεομένην δὲ ὕστερον τούτων ἐπέλαβεν ἡ τελευτὴ μανέντα· ὡς γὰρ δὴ ἐλάβετο ξίφους, ἐτίτρωσκεν αὐτὸς αὑτὸν καὶ διεξῄει τὸ σῶμα ἅπαν κόπτων τε καὶ λυμαινόμενος. Ἀργεῖοι μὲν δὴ τοῖς ἱκέταις τοῦ Ἄργου διδόντα αὐτὸν δίκην τέλος τοῦ βίου φασὶν εὑρέσθαι τοιοῦτον, Ἀθηναῖοι δὲ ὅτι ἐδῄωσε τὴν Ὀργάδα, Δελφοὶ δὲ τῶν δώρων ἕνεκα ὧν τῇ προμάντιδι ἔδωκεν, ἀναπείσας ἐψευσμένα εἰπεῖν ἐς Δημάρατον.
Demaratus was indeed deprived of his kingship through the hatred of Cleomenes, and not according to justice; Cleomenes himself, afterward, met his end through madness. For, having grasped his sword, he wounded himself, mutilating and hacking all parts of his body. The Argives say his life met such an end because he was thus paying the penalty for the suppliants from Argos; the Athenians say it was because he devastated Orgas; and the Delphians declare it was owing to the gifts he gave the priestess, persuading her to give false oracles about Demaratus.