In Book III of the Histories, Herodotus relates that a magus had secretly assassinated the Persian king Smerdis and taken his place on the throne. Otanes, in this account, is both the uncle and the father-in-law of Smerdis; from his daughter Phaedymia, he obtains evidence that the man on the throne is not the real Smerdis. The real Smerdis had his ears intact, while the ears of the impostor are missing — indicating that he had committed a crime against the king. Otanes gathers six noble Persians and plots to get rid of the false Smerdis. They then hold a contest whereby whichever of them got his horse to neigh first after sunrise shall become king. Otanes withdraws from this contest, asking only that he and his descendants be given their independence from royal rule. Darius cheats and ascends the throne.
There follows a discussion between Darius, Otanes and Megabyzus on the relative merits of monarchy, oligarchy and democracy as forms of government. Otanes speaks up for democracy.
As an early defender of democracy in Greek literature, Otanes has been used as a point of reference in a number of subsequent political discussions. Jean-Jacques Rosseau refers to Otanes in his notes to Discourse on the Origin of Inequality. Otanes is also mentioned in Isiah Berlin's seminal lecture "Two Concepts of Liberty": "As for Otanes, he wished neither to rule nor to be ruled — the exact opposite of Aristotle's notion of true civic liberty". Otanes has his own conception of freedom.
Otanes also appears in certain works of fiction and drama. James Baldwin (1841-1925) fictionalizes the childhood of Otanes in his short story, "The Boy and The Robbers" from his book, "Fifty Famous People — A book of short stories". In addition, the Dutch TV movie Volk en vaderliefde ('People and Fatherly Love', 1976) is about Otanes and the coup.
- Herodotus. History of Herodotus, Volume 2. pp. 384–396.
- Rosseau, Jean-Jacques (1992-11-13). Discourse on the origin of inequality. Hackett Publishing. p. 71.
- Berlin, Isaiah (2004). Liberty. Oxford University Press. p. 33.
- Baldwin, James. The Boy and The Robbers, in Fifty Famous People. Kessinger Publishing Co. ISBN 1-4191-1963-X.
- Volk en vaderliefde (TV 1976) at the Internet Movie Database