Passage 3.20.9
προϊοῦσι δὲ Ἵππου καλούμενον μνῆμά ἐστι. Τυνδάρεως γὰρ θύσας ἐνταῦθα ἵππον τοὺς Ἑλένης ἐξώρκου μνηστῆρας ἱστὰς ἐπὶ τοῦ ἵππου τῶν τομίων· ὁ δὲ ὅρκος ἦν Ἑλένῃ καὶ τῷ γῆμαι προκριθέντι Ἑλένην ἀμυνεῖν ἀδικουμένοις· ἐξορκώσας δὲ τὸν ἵππον κατώρυξεν ἐνταῦθα. κίονες δὲ ἑπτὰ οἳ τοῦ μνήματος τούτου διέχουσιν οὐ πολύ, κατὰ τρόπον οἶμαι τὸν ἀρχαῖον, οὓς ἀστέρων τῶν πλανητῶν φασιν ἀγάλματα. καὶ Κρανίου τέμενος κατὰ τὴν ὁδὸν ἐπίκλησιν Στεμματίου καὶ Μυσίας ἐστὶν ἱερὸν Ἀρτέμιδος.
Going forward, one encounters a tomb called the "Tomb of the Horse." Here Tyndareus once sacrificed a horse and made all the suitors of Helen swear an oath upon the severed parts of the animal. The oath bound them to defend Helen and the chosen husband, should either suffer injustice. Having made them swear this oath, Tyndareus buried the horse on this spot. Nearby stand seven columns, placed at a short distance from the tomb, which, according to ancient custom, are said to be symbols representing the planets. Along the road lies also a sanctuary of Kranius, surnamed Stemmatios, and a shrine belonging to Mysian Artemis.