Résumé : Herodotus’ so called “Persian debate” (III, 80-82) marks the emergence not only of Greek but of all political theory properly so called. This paper engages with Otanes’ speech, and, more precisely, with the second part of his speech, concerning isonomia (III, 80, 25 – 31). It aims at examining some aspects of Otanes’ concept of isonomia, placing them within the broader intellectual context of their time, as well as at pointing out the surprising modernity of the issues the above passage raises.