Passage 2.25.7
ἐρχομένοις δὲ ἐξ Ἄργους ἐς τὴν Ἐπιδαυρίαν ἐστὶν οἰκοδόμημα ἐν δεξιᾷ πυραμίδι μάλιστα εἰκασμένον, ἔχει δὲ ἀσπίδας σχῆμα Ἀργολικὰς ἐπειργασμένας. ἐνταῦθα Προίτῳ περὶ τῆς ἀρχῆς πρὸς Ἀκρίσιον μάχη γίνεται, καὶ τέλος μὲν ἴσον τῷ ἀγῶνι συμβῆναί φασι καὶ ἀπʼ αὐτοῦ διαλλαγὰς ὕστερον, ὡς οὐδέτεροι βεβαίως κρατεῖν ἐδύναντο· συμβάλλειν δὲ σφᾶς λέγουσιν ἀσπίσι πρῶτον τότε καὶ αὐτοὺς καὶ τὸ στράτευμα ὡπλισμένους. τοῖς δὲ πεσοῦσιν ἀφʼ ἑκατέρων--- πολῖται γὰρ καὶ συγγενεῖς ἦσαν---ἐποιήθη ταύτῃ μνῆμα ἐν κοινῷ.
To those traveling from Argos into the territory of Epidaurus, there is a building on the right hand side closely resembling a pyramid, upon which are engraved Argive-shaped shields. At this place, Proetus fought with Acrisius for the kingship. They say that the battle resulted in a draw, and reconciliation followed afterward, as neither could gain a decisive victory. They also claim this was the first occasion when they and their armies fought equipped with shields. The fallen from each side—who were citizens and kinsmen—were jointly buried together there, and a common memorial was made for them at this spot.