“The Melian Dialogue” is found within Thucydides's larger work, History of the Peloponnesian War, published sometime in the late fifth century BCE, shortly after the conclusion of the events described within. The work is divided into eight “books.” “The Melian Dialogue” is located in Book 5, about halfway through the entirety of the work (and the war). It dramatizes a negotiation between Athens, one of the two great warring powers of the Greek world, and Melos, a tiny, neutral island in the middle of the Aegean sea. Athens intends to conquer Melos, and in these negotiations, the Athenian delegation clearly has the upper hand. They offer the Melians not a deal but an ultimatum: Surrender unconditionally or face “annihilation.” This is a unique passage in the book, as it is the only instance of a dramatized dialogue, whereas the remainder of the story is given in narration and, occasionally, oratory. Thucydides did not personally witness the negotiations. Having served as a general on the Athenian side, he was exiled from Athens for failing to prevent Spartan forces from capturing the city of Amphipolis. Following his exile from Athens, he spent the remaining 20 years of the war traveling the Greek world, gathering the perspective of the opposing side as well as his own. His work is widely regarded as the earliest instance of what we recognize as history today: a dispassionate recounting of events with impartial analysis of the facts, without regard to outside (supernatural) forces. The dramatization of the Melian dialogues, in particular, is a work of imagination based on Thucydides’s knowledge of both Athenian and Melian worldviews. While the larger History is a rich exploration of imperialism and the clash between two hegemonic powers (Athens and Sparta), “The Melian Dialogue” offers the perspective of a tiny, independent nation that finds itself in the way of those hegemonic aspirations. It has often been taught as a foundational document of political realism, as the Athenians offer no moral justification for their conquest of Melos, saying only, in Thucydides’s famous formulation, “The strong do what they can, and the weak suffer what they must.” 

The History of the Peloponnesian War survives to the present age thanks to a series of medieval manuscripts and ancient papyrus fragments. It stops abruptly, mid-sentence, the "Funeral Oration Of Pericles" is the most well-known portion of the text. Selections from The History of the Peloponnesian War also appear in On Justice Power and Human Nature. There have been many translations of the work, but this guide uses the most recent English translation, Martin Hammond’s The Peloponnesian War, published by Oxford University Press in 2009.

The passage containing “The Melian Dialogue” opens in the typical narrative fashion of The History of the Peloponnesian War, with a recounting of events, noting that the Athenians sent a force to the Melians to coerce them into joining their empire. Though the Melian’s shared a Dorian ethnic heritage with the Spartans, they had been an independent state for centuries and had remained neutral in the war up to this point. The Athenians land their military force and send forth a spokesman to negotiate with the Melians, who send out a delegation of prominent citizens to meet them; thus begins the dialogue.

The Athenians propose a discussion wherein they will lay forth their arguments, and at any time the Melians may object and make counter-arguments. The Melians accede to this on principle, though they doubt that they can come out ahead: If they win the debate, they will be attacked; if they lose, they give up their freedom. Then the debate begins in earnest.

The Athenians preface their main point with an allusion to their role in the Persian Wars, a 50-year conflict that had concluded in 449 BCE, less than 20 years before the start of the Peloponnesian War. Because they had been instrumental in repelling the Persians’ attempted conquests, the Athenians believe they have a right to leadership of the Greek world. They then declare that though Melians have done them no wrong, they are nonetheless compelled to subjugate them on grounds of practicality. This is the classic statement of political realism: There is no fairness between parties of unequal strength; the stronger party makes decisions based not on fairness or justice but on expediency. Noting the injustice of the situation, the Melians assert that it is in the Athenians’ practical interest to uphold principles of fair play, lest they fall victim to similar bullying in the future.

The Athenians, however, aren’t afraid of being conquered by another great power like Sparta. Their chief concern is the possibility of being overthrown from below. Their empire has grown so large that the real danger comes from unrest among the peoples they have conquered. Nevertheless, they attempt to persuade the Melians that submission is in their own best interests, too: The Athenians wouldn’t gain anything if they were “forced” to destroy them due to their refusal. The Melians protest: In that case, Melos should be allowed simply to remain neutral. Yet the Athenians contend that allowing neutrality will make them look weak and invite rebellion. The Melians reply that if Athens develops a reputation for attacking neutral parties, other neutral cities will turn to the Spartans for protection. The Athenians are not concerned, however. In their view, the greatest threat comes from the smaller cities they control—and from those they don’t yet control.

Questions of justice and neutrality aside, the discussion now turns to more abstract values: Resistance is a matter of self-respect, and the Melians argue that submitting to Athenian rule will damage the city’s honor. The Athenians assert that, given the power discrepancy, the Melians should think only of their survival, not honor. The Melians respond that fortune is fickle in war, and there may yet be some hope so long as they fight. The Athenians reply that to trust in such vanishingly small hope would be illogical—the equivalent of trusting in supernatural forces, divination, and oracles. The Melians argue that the Spartans will feel bound by honor to come to the aid of their kin, but the Athenians consider this hope equally foolish: Sparta is a hegemonic power like Athens and will therefore act as Athens does, which is in its own best interests. In addition, the Spartans are risk-averse, acting only when victory seems assured.

The Athenians concede that a Melian victory is not impossible, but they emphasize that it is extremely unlikely. In the Athenian view, the Melians have made no strong, logical arguments as to why they should not submit. The Athenians reiterate that the two sides are not equal, and so only practicality should prevail: gain for the Athenians, survival for the Melians. They briefly withdraw and await their response. The Melians answer: If Athens will not accept their neutrality, then they will resist, placing their trust in both the gods and the Spartans. The Athenians’ final word condemns the Melians for placing their future in the hands of mere chance, rather than relying on evidence and rational judgement.

The dialogue ends, and the Athenians lay to siege the city. The siege drags on for about half a year until ultimately hardship, and a betrayal by one of their own, forces Melos to surrender. To make an example of the rebellious city, the Athenians massacre the adult males, sell the women and children into slavery, and resettle the land with their own people.