Passage 3.15.5
τοῦτο Ἡρακλέα μάλιστα ἐξηγρίωσεν ἐς Ἱπποκόωντα καὶ τοὺς παῖδας· αὐτίκα δὲ ὡς ὀργῆς εἶχε χωρεῖ σφισιν ἐς μάχην. τότε μὲν δὴ τιτρώσκεται καὶ λαθὼν ἀπεχώρησεν· ὕστερον δὲ ἐξεγένετό οἱ στρατεύσαντι ἐς Σπάρτην τιμωρήσασθαι μὲν Ἱπποκόωντα, τιμωρήσασθαι δὲ καὶ τοὺς παῖδας τοῦ Οἰωνοῦ φόνου. τὸ δὲ μνῆμα τῷ Οἰωνῷ πεποίηται παρὰ τὸ Ἡρακλεῖον.
This especially inflamed Heracles against Hippocoön and his sons, and immediately, in his anger, he moved to fight against them. On that occasion he was wounded, and secretly withdrew. Later, however, when he marched upon Sparta with an army, he succeeded in avenging himself upon Hippocoön, and also avenged the death of Oionos's sons. The tomb of Oionos was erected near the sanctuary of Heracles.