History of the Peloponnesian War — themes & analysis

Thucydides states his purpose at the start of Book 1 with the kind of austere clarity that has shaped historical writing ever since. He has set down his work, he says, not as a prize composition for the moment but as a possession for all time — a ktema es aei. The phrase has been quoted to exhaustion, but its content is precise and unsentimental. Human nature, on Thucydides's reading, does not fundamentally change; the political and military situations human beings find themselves in repeat with sufficient regularity that a careful account of one such situation can usefully inform later participants in similar ones.

He is therefore writing not for the entertainment of his contemporaries but for the instruction of statesmen and generals he will never meet. The doctrine licenses his exclusion of much that other historians of his time included — the supernatural, the mythological, the merely entertaining — and his concentration on what is, in his judgment, structurally repeatable. It also commits him to a kind of relentless precision that his Greek readers must have found chilly. There are no charming digressions, almost no descriptions of foreign customs, very little colour. There is the war, the speeches and councils that produced it, the actions and outcomes that followed.

The first reader who fully grasped what Thucydides was doing was the Roman historian Sallust in the first century BCE; the doctrine runs through Tacitus, Machiavelli, Hume, and the entire modern academic discipline of international relations. Students at war colleges still read the Melian Dialogue and Pericles's funeral oration as primary texts — not as historical curiosities but as working analytical tools.

The History is in this sense the founding document of professional historical writing as we know it. No other work of comparable age has generated comparable scholarly controversy about method, reliability, and the nature of historical knowledge — and none has proven more durably useful to practitioners of the craft it invented.

Where to follow it: Book 1 Ch. I (the methodological preface), Book 1 Ch. II (the Archaeology).

One of the most famous and argued-over passages in the History is Thucydides's note on his method for the speeches that occupy a great deal of the text. Throughout the work, generals address their troops, ambassadors address foreign assemblies, politicians address their cities. The speeches are often long and densely argued, and they constitute much of the political content of the History. Thucydides confesses, in 1.22, that he did not always have access to a verbatim record of what was said.

His method, he says, was to write the speeches as they seemed to him most likely to have been, given what the situation required of the speakers, while keeping as close as possible to the general sense of what was actually said. Modern readers have argued ever since about how much latitude this allowed him. The conservative view is that the speeches are essentially Thucydides's own analysis of the political situation, given dramatic form by being placed in the mouths of the participants. The more permissive view is that they are based, where possible, on real reports and memories.

What is clear is that the speeches are the place where Thucydides is most directly present as a political analyst. The most famous of them — Pericles's funeral oration, the Mytilenean debate, the Melian Dialogue, Alcibiades's speech for the Sicilian expedition — are not so much records of past oratory as the most concentrated political philosophy fifth-century Athens produced.

To read Thucydides is to read simultaneously a chronicle of events and a sustained meditation on the structure of political action, and the speeches are the joint where the two halves meet. This double function — documentary and analytical — is what distinguishes the History from everything written before it and much written since.

Where to follow it: Book 1 Ch. I (method note 1.22), Book 1 Ch. III (Corinthian and Athenian speeches at Sparta), Book 2 Ch. VII (Pericles's funeral oration), Book 5 Ch. XVII (the Melian Dialogue).

Book 2 of the History contains the most quoted single passage in classical political literature, Pericles's funeral oration for the Athenians killed in the first year of the war. The speech is delivered at the public funeral of the war dead in the winter of 431-430 BCE, in front of the Kerameikos cemetery outside the walls of Athens. It is, in form, a praise of the dead; in substance, a praise of the Athens for which they had died.

Pericles describes the Athenian constitution — democracy, in which advancement is by ability rather than by class, and in which the laws are obeyed because they are the laws of the citizens themselves. He claims, in the most quoted single line, that Athens is the school of Hellas, an education to all of Greece. The oration is the most idealised statement of Athenian self-understanding ever written, and Thucydides places it deliberately at the beginning of the war, before plague, defeat, atrocity, and finally surrender have made every claim in it look more questionable.

Pericles dies of the plague in the next chapter; the city he is praising will, within a single book, vote to massacre an entire allied city for revolting; within five books it will commit, at Melos, an act of state cruelty Pericles would have flinched from; within six and seven, it will destroy itself in Sicily; within ten, it will surrender. The funeral oration is not undone by what follows, but everything that follows is read against it.

The gap between the ideal and the events is the moral pressure of the History. Thucydides never names this gap or moralises about it; he simply places the speech where it will do the most structural work, and trusts the reader to feel it accumulate over the remaining six books.

Where to follow it: Book 2 Ch. VII (funeral oration and plague), Book 2 Ch. VI (first Spartan invasion; Pericles restrains the demos).

Book 5 contains the most direct statement of political realism in any ancient text — the dialogue between Athenian envoys and the council of the small island state of Melos in 416 BCE. The Athenians have arrived to demand Melian submission. Melos, a Spartan colony but neutral in the war, refuses. Rather than narrating a long debate, Thucydides constructs the conversation as a back-and-forth between the Athenian negotiators and the Melian council.

The Athenians, with a flatness that has shocked readers ever since, dispense with the conventional language of justice. We will not bother with high-sounding talk about how our empire is justly held, they say, and you should not bother about how Sparta will come to your aid. The relevant facts are these: in matters of international relations, the strong do what they can and the weak suffer what they must. The Melians appeal to the gods, to fortune, to Spartan kinship; the Athenians counter each appeal with cold practical analysis.

Melos refuses, and after a siege the Athenians take the city, kill the men of military age, and sell the women and children into slavery. The episode is the most famous statement in classical literature of the doctrine that justice between political actors is, in the limiting case, a function of relative power. The centuries of debate about whether Thucydides endorsed the Athenian position, condemned it, or refused to take a side are more or less the centuries of debate between political realism and its critics.

The structural argument is tight: the Melian Dialogue sits at the end of Book 5, immediately before the Sicilian disaster in Books 6 and 7 — the Athenians ruining themselves by exactly the kind of overreach the Melians had warned against. Whether or not Thucydides moralises, the arrangement of the text speaks plainly.

Where to follow it: Book 5 Ch. XVII (the Melian Dialogue), Book 6 Ch. XVIII (the Sicilian debate begins).

Books 6 and 7 of the History are the centrepiece of the work and the longest sustained tragic narrative in classical historiography. In 415 BCE, Athens, despite being already at war with Sparta and at the limits of its resources, votes to send an enormous expedition to Sicily to conquer Syracuse. The vote is driven by the brilliant, dangerous young aristocrat Alcibiades, who promises that Sicily will fall easily and that its resources will then make Athens unstoppable. The cautious general Nicias, hoping to dampen the enthusiasm by laying out the logistical demands, succeeds only in convincing the assembly to send a larger force than originally planned.

The expedition sails. Alcibiades is recalled almost immediately on charges of religious sacrilege, defects to Sparta, and from Sparta advises the Spartans how to undo Athens. Nicias, ill and indecisive, delays the assault on Syracuse long enough for the city to fortify itself and for Spartan reinforcements under Gylippus to arrive. The Athenian fleet is bottled up in the Great Harbour of Syracuse and destroyed in two desperate naval battles.

The army attempts to retreat overland, is harried, surrounded, and forced to surrender. Nicias and Demosthenes are executed; the surviving prisoners are penned in the stone quarries of Syracuse and die over the following months of thirst, exposure, and disease. Thucydides reports the closing scenes with a restraint that has not been improved on. The entire arc — the overconfident vote, the decisive intervention by ambition (Alcibiades) and indecision (Nicias), the slow tightening of the Syracusan defence, the catastrophe in the harbour, the long retreat, the quarries — is the structural demonstration of every theme the History has been developing.

The same democratic system that produced Pericles produced Alcibiades. The same Athens that praised itself as the school of Hellas in Pericles's oration ended up dying of thirst in a stone quarry in Sicily ten years later. The two long books are the most carefully built tragedy in any work of European historical writing.

Where to follow it: Book 6 Ch. XVIII (the debate, the vote), Book 6 Ch. XIX (the Syracusan debate), Book 6 Ch. XX (Alcibiades in Sparta), Book 7 Ch. XXI (Nicias's letter), Book 7 Ch. XXII (Demosthenes arrives), Book 7 Ch. XXIII (the harbour battles).