Passage 5.6.8
αὕτη προαποθανόντος αὐτῇ τοῦ ἀνδρός, ἐξεικάσασα αὑτὴν τὰ πάντα ἀνδρὶ γυμναστῇ, ἤγαγεν ἐς Ὀλυμπίαν τὸν υἱὸν μαχούμενον· νικῶντος δὲ τοῦ Πεισιρόδου, τὸ ἔρυμα ἐν ᾧ τοὺς γυμναστὰς ἔχουσιν ἀπειλημμένους, τοῦτο ὑπερπηδῶσα ἡ Καλλιπάτειρα ἐγυμνώθη. φωραθείσης δὲ ὅτι εἴη γυνή, ταύτην ἀφιᾶσιν ἀζήμιον καὶ τῷ πατρὶ καὶ ἀδελφοῖς αὐτῆς καὶ τῷ παιδὶ αἰδῶ νέμοντες---ὑπῆρχον δὴ ἅπασιν αὐτοῖς Ὀλυμπικαὶ νῖκαι---, ἐποίησαν δὲ νόμον ἐς τὸ ἔπειτα ἐπὶ τοῖς γυμνασταῖς γυμνοὺς σφᾶς ἐς τὸν ἀγῶνα ἐσέρχεσθαι.
After her husband had died, she disguised herself completely, taking on the likeness of a male trainer, and she brought her son to Olympia to compete. When her son Peisirodus was victorious, Callipateira jumped over the barrier that enclosed the trainers, and her clothing came loose, revealing her as a woman. Once she was discovered to be female, they acquitted her without punishment, out of respect for her father, her brothers, and her son, all of whom were Olympic victors. However, they established a law for the future: that trainers must enter the competition area naked.