The Peloponnesian War

1. Causes — The Rivalry of Two Giants

In the second half of the fifth century BC the Greek world was dominated by two great powers: Athens, a naval democracy ruling a rich island-and-coast empire, and Sparta, a landlocked military oligarchy heading the Peloponnesian League. Thucydides, the greatest ancient analyst, states the underlying cause plainly: "what made war inevitable was the growth of Athenian power and the fear which this caused in Sparta." The immediate triggers were all in the west: Athens' support of Corcyra (Corfu) against its mother-city Corinth, Athens' siege of Potidaea (a Corinthian colony in the Athenian alliance), and the Megarian Decree that excluded Megara from Athenian markets. Corinth, feeling directly threatened, pressed its ally Sparta to act, and in 431 BC the war began when Thebes attacked Plataea, an ally of Athens (World History Encyclopedia, "Peloponnesian War," worldhistory.org/peloponnesian_war/).

2. Pericles’ Strategy and the Great Plague (430 BC)

Athenian strategy, devised by Pericles, was to avoid pitched battles against the superior Spartan land army, withdraw behind the city's Long Walls (which linked Athens to its port of Piraeus), and use the fleet to raid the Peloponnese and keep supply lines open. The Spartans, under King Archidamus, responded by annually ravaging the Attic countryside. The strategy was sound, but it had a catastrophic flaw: the crowded evacuation of the countryside into the walled city bred disease. In 430 BC a terrible plague swept Athens, killing perhaps a third of its population — including Pericles himself in 429 BC. With his death, Athens lost its steady guiding hand and fell under the sway of more reckless leaders (World History Encyclopedia, "Peloponnesian War," worldhistory.org/peloponnesian_war/).

The war then settled into a pattern of raids, minor campaigns and periodic truces. A one-year truce in 423 BC and then the Peace of Nicias in 421 BC (named for the Athenian general Nicias) brought a fragile armistice, but it was never truly peaceful, and the underlying rivalry soon flared again.

3. The Brilliant Turncoats — Brasidas and Alcibiades

The middle phase of the war was dominated by two extraordinary individuals. The Spartan general Brasidas (d. 422 BC) was a bold commander who campaigned in Thrace in 424–422 BC, capturing the crucial Athenian colony of Amphipolis — whose loss caused the exile of the historian Thucydides, banished for failing to save it and who then wrote his history in exile. Brasidas and the Athenian leader Cleon, who had won fame by capturing the island of Sphacteria from Sparta (425 BC), both died in battle at Amphipolis in 422 BC. Their deaths removed the extremists and opened the way for the Peace of Nicias (World History Encyclopedia, "Brasidas," worldhistory.org/brasidas/).

Far more dazzling was Alcibiades (c. 450–404 BC), the brilliant, aristocratic, extravagant and unreliable nephew of Pericles. Flamboyant and hugely talented, he persuaded the Athenians to abandon the cautious peace for an adventurous, expansionist policy. Facing prosecution for profaning the sacred mysteries, he fled to Sparta and then to Persia, giving each his military expertise in turn, before eventually being recalled to command the Athenian fleet. A man of genius and betrayal, Alcibiades embodies the volatile energy of late fifth-century Athens (World History Encyclopedia, "Alcibiades," worldhistory.org/alcibiades/).

4. The Sicilian Expedition (415–413 BC) — The Turning Point

In 415 BC, egged on by Alcibiades despite the caution of Nicias, the Athenians launched the most ambitious and, as it proved, most catastrophic venture of the war: a huge expedition to conquer Syracuse in Sicily and bring the rich island into the Athenian empire. The fleet and army were among the largest and best-equipped Athens ever sent out. But the expedition unravelled: Alcibiades was recalled to face trial (and instead defected to Sparta); Nicias commanded indecisively; the Syracusans, advised by the Spartan general Gylippus, built their walls and fought back; and the Athenians were trapped. In 413 BC the entire expeditionary force was destroyed in a disastrous attempt to retreat — thousands (including Nicias) were killed or enslaved in the quarries of Syracuse. The disaster was so complete that, in Thucydides' words, to Athens it was "the ruin of the whole undertaking" and a blow from which the empire never recovered (World History Encyclopedia, "Sicilian Expedition," worldhistory.org/Sicilian_Expedition/).

5. The Ionian War and Persian Money (c. 412–405 BC)

The empire, shaken, began to disintegrate: allies revolted, and the Spartans — now advised by Alcibiades — established a fort at Decelea in Attica, cutting Athens off from its silver mines and farmland. In 412 BC Sparta made a fateful alliance with Persia, trading recognition of Persian claims in Ionia for money to build a fleet. It was Persian gold that ultimately tipped the naval balance. Athens, though, fought back tenaciously, winning successes under a recalled Alcibiades (victory at Cyzicus, 410 BC) and restoring some of its position. Internal instability — including an oligarchic coup, the rule of the Four Hundred in 411 BC, soon overthrown — marked these troubled years, all chronicled by Thucydides and then by Xenophon (World History Encyclopedia, "Peloponnesian War," worldhistory.org/peloponnesian_war/).

6. Aegospotami and the Fall of Athens (405–404 BC)

The end came at sea. The brilliant Spartan admiral Lysander, a sort of Spartan Themistocles, spent Persian money to build a superb fleet and then, in 405 BC, caught the entire Athenian navy beached and unprepared at Aegospotami in the Hellespont. In a single stroke Lysander captured or destroyed almost the whole Athenian fleet — the city's lifeblood. With its grain supply from the Black Sea cut off, Athens had no choice but to surrender in 404 BC. The war was over.

The peace was harsh: the Long Walls and the fortifications of Piraeus were demolished to the sound of flute-music, the empire was dissolved, the fleet reduced to a dozen ships, and a brutal pro-Spartan oligarchy — the infamous Thirty Tyrants — was imposed on Athens. The Golden Age was extinguished; Greece, exhausted and impoverished, had spent its strength in self-destruction, and the stage was set for a new power and a new kind of Greek history (World History Encyclopedia, "Peloponnesian War," worldhistory.org/peloponnesian_war/).

7. The Trial and Death of Socrates (399 BC)

The war’s legacy included one of the defining events of western history. In the charged, disheartened and partisan atmosphere of defeated Athens, the philosopher Socrates — a fierce critic of democracy and of unexamined opinion, and a friend of the discredited Alcibiades and Critias (a leader of the Thirty Tyrants) — was put on trial in 399 BC, charged with impiety and corrupting the youth. Condemned, he refused to escape and drank the hemlock, accepting death rather than renounce his philosophical mission. His trial and death, recorded by Plato in the Apology and Phaedo, made him the martyr of philosophy and the enduring symbol of the examined life. From his death his student Plato built the philosophy that would dominate the western world (Internet Encyclopedia of Philosophy, "Socrates," iep.utm.edu/socrates/).

7b. The Cost and Character of Athenian Empire

To understand the Peloponnesian War one must understand the Athenian empire that provoked it. What had begun as the voluntary Delian League (478 BC) had by the 440s become a tribute-paying empire: allies’ ships gave way to payments of money (phoros), assessed each year by Aristides, the "Just," and the treasury was moved from Delos to Athens (454 BC). Athens used the tribute to pay for its great fleet, its public buildings (including the Parthenon) and the pay of its citizens; it maintained strict control over the "allies," installed its own officials and garrisons, favoured democracies, and moved colonists into allied lands. Members who tried to leave — Naxos, Thasos, Samos — were forcibly reduced; the island of Melos, which remained neutral, was conquered and its men killed and women enslaved (416 BC), an atrocity that Thucydides dramatises in the chilling "Melian Dialogue" on the naked logic of power. To its own citizens Athens was a free democracy; to the allied states it was a tyrant city, and this double nature — "in name a democracy, in reality the rule of the first man," Thucydides said of the Periclean age — was the root both of Athenian greatness and of the hatred that arrayed half of Greece against it. The war that followed was fought, in part, to end that empire — and when Athens fell in 404 BC, the empire fell with it, broken forever (World History Encyclopedia, "Delian League," worldhistory.org/Delian_League/).

7c. Warfare in the Peloponnesian War — Plataea to Sphacteria and Pylos

The Peloponnesian War saw warfare evolve beyond the simple hoplite clash. The opening act — the siege of Plataea (429–427 BC), where the Thebans and Spartans besieged and finally starved the small Boeotian town loyal to Athens, then executed its defenders — set a grim tone of siege and atrocity. New tactics emerged: the Athenians developed light-armed forces and the use of surprise, so that at Pylos (425 BC) the general Demosthenes established a fort on the Messenian coast, and the Athenians trapped and captured some 300 Spartan hoplites on the neighbouring island of Sphacteria — a humiliating blow to Spartan prestige, since Sparta’s invincibility had lain in its hoplite citizens never surrendering. The war also widened to distant theatres: the circumnavigation of the Peloponnese by Athenian fleets, raids on the coast, and campaigns in Thrace, the Aegean and eventually Sicily. As the war ground on, both sides turned to money, mercenaries and (for Athens) the tribute of what allies remained; Sparta, lacking funds, finally accepted Persian gold (412 BC) to build the fleet that would win the war, in exchange for recognising Persian claims in Ionia. The war thus fatally entangled Greek politics with both the persistence of the Athenian empire and the intervention of Persia — a combination that exhausted and impoverished the whole Greek world (World History Encyclopedia, "Peloponnesian War," worldhistory.org/peloponnesian_war/).

7d. The Revolutions of Athens — The Four Hundred and the Thirty Tyrants

The strains of the war repeatedly overturned the institutions of Athens. After the disasters of 413 BC, a reactionary movement — led by the oligarchs under Antiphon, Phrynichus and others, and encouraged by Alcibiades from exile — overthrew the democracy in 411 BC, establishing a narrow ruling council of Four Hundred, soon replaced by a broader oligarchy of Five Thousand. The democracy was restored the next year, but the revolution had shown how fragile it was under stress. Far worse came in defeat: in 404 BC, under the protection of the Spartan conqueror Lysander, an extreme oligarchy known as the Thirty Tyrants (led by Critias, a former pupil of Socrates, and Theramenes) seized power with Spartan backing, confiscated property, executed hundreds of citizens including some of the most eminent, and earned the name "Thirty Tyrants" for its cruelty. The Thirty were overthrown within a year by the returning democrats under Thrasybulus, who defeated their forces at Munichia in Piraeus (403 BC) and restored the democracy, which then survived, remarkably, for another eighty years. These revolutions — and the role in them of Socrates’ associates — were the background against which Socrates was tried and condemned in 399 BC, and they taught the Greeks, and posterity, both the resilience and the fragility of democratic institutions (World History Encyclopedia, "The Thirty Tyrants," worldhistory.org/Thirty_Tyrants/).

8. Selected Sources & Further Reading

What made war inevitable was the growth of Athenian power and the fear which this caused in Sparta.— Thucydides, History of the Peloponnesian War I.23 (trans. R. Crawley)