The assassination of the False Smerdis in Book 3 and the ensuing constitutional uncertainty offer Herodotus an inflection point to pause and consider the institution of monarchy in Persia in terms of its strengths and weaknesses. This chapter reexamines the speeches given by the conspirators in advance of the coup and its aftermath. In these episodes, Darius undermines a key nomos held by the Persians, their abhorrence of falsehood. Darius does so as a private citizen but given his subsequent rise to the throne, this invites comparison with the Great Kings. Darius’ disregard for nomos opens a philosophical debate on human motivation and self-interest. In a speech to the Persian conspirators, the future monarch defends "egoism," the philosophy that all action is performed to maximize the individual’s self-interest. This view is set alongside orations by the Persians Otanes and Prexaspes, exponents of cooperative action and altruism, respectively. The chapter argues that fifth-century intellectual culture engaged in a spirited interrogation of the individual in relation to self-interest, often in terms of the social contract. The clash between motivation on behalf of the one versus the many will illustrate the complex negotiation in Persia of ruler and ruled, self and society.