The Peloponnesian War

431–⁠405 BCEAthens and the Greek world, not on the map

about 2,443 years ago

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The war of 431–404 BCE between the Athenian-led Delian League and the Spartan-led Peloponnesian League, which Sparta won.

The Peloponnesian War was fought in the Eastern Mediterranean between the Athenian-led Delian League and the Spartan-led Peloponnesian League from 431 to 404 BC for hegemony over Ancient Greece.

allowed the Spartan coalition to decisively defeat Athens, beginning a period of Spartan hegemony over Greece

From Wikipedia, Peloponnesian War (opens en.wikipedia.org), as of 2026-08-22.

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In short

It was fought for hegemony over Greece and stayed inconclusive until Persia backed Sparta in 413 BCE.

from 431 to 404 BC for hegemony over Ancient Greece. Initially inconclusive, the intervention of the Persian Empire in support of Sparta in 413 BC allowed the Spartan coalition to decisively defeat Athens
From Wikipedia, Peloponnesian War (opens en.wikipedia.org), as of 2026-08-22.
Athens lost its Aegean empire and its dominance at sea, while Sparta became the leading power of Greece.

Athens lost its Aegean empire and its maritime dominance, while Sparta became established as the leading power of Greece.
From Wikipedia, Peloponnesian War (opens en.wikipedia.org), as of 2026-08-22.
The war between democratic Athens’ alliance and oligarchic Sparta’s became a total war of ideologies, and civil war grew common.

the conflict between the democratic Athenian alliance and the oligarchical Spartan alliance transformed it into total war between competing political ideologies, making civil war between those factions a common occurrence in the Greek world.
From Wikipedia, Peloponnesian War (opens en.wikipedia.org), as of 2026-08-22.

How it began

Thucydides wrote that the growth of Athenian power, and the alarm it inspired in Lacedaemon, made war inevitable.

Thucydides summarised the situation before the war as: "The growth of the power of Athens, and the alarm which this inspired in Lacedaemon, made war inevitable".
From Wikipedia, Peloponnesian War (opens en.wikipedia.org), as of 2026-08-22.
Athens made a defensive alliance with Corcyra , and Corinth secretly sent men into besieged Potidaea, breaking the Thirty Years’ Peace.

Athens discussed with both Corcyra and Corinth, and made a defensive alliance with Corcyra.
During the subsequent Battle of Potidaea, the Corinthians unofficially aided Potidaea by sneaking contingents of men into the besieged city to help defend it. This directly violated the Thirty Years' Peace
From Wikipedia, Peloponnesian War (opens en.wikipedia.org), as of 2026-08-22.
The Spartan assembly voted that Athens had broken the peace, in effect declaring war; King Archidamus II had spoken against the war.

The Spartan king Archidamus II spoke against the war, but the opinion of the hawkish ephor Sthenelaidas prevailed in the Spartan ecclesia.
A majority of the Spartan assembly voted to declare that the Athenians had broken the peace, essentially declaring war.
From Wikipedia, Peloponnesian War (opens en.wikipedia.org), as of 2026-08-22.

The first ten years

The first attack was by the Thebans on the Athenian outpost at Plataea , on 4 April 431 BCE.

The first attack was by the Thebans on the Athenian outpost at Plataea, on 4 April 431 BC.
From Wikipedia, Peloponnesian War (opens en.wikipedia.org), as of 2026-08-22.
In 431 BCE the Spartan king Archidamus II invaded Attica ; many citizens of Attica left their farms and moved inside the Long Walls.

began in 431 BC when the Spartan king Archidamus II invaded Attica with his army.
Many of the citizens of Attica abandoned their farms and moved inside the Long Walls, which connected Athens to its port of Piraeus.
From Wikipedia, Peloponnesian War (opens en.wikipedia.org), as of 2026-08-22.
Plague hit Athens in 430 BCE, killing Pericles and an estimated third to two-thirds of the population.

In 430 BC, an outbreak of a plague hit Athens.
The plague wiped out over 30,000 citizens, sailors and soldiers, including Pericles and his sons. Roughly one-third to two-thirds of the Athenian population died.
From Wikipedia, Peloponnesian War (opens en.wikipedia.org), as of 2026-08-22.
Athens gained the upper hand at Sphacteria in 425 BCE. In a shock, 300 Spartan hoplites encircled by Athenian forces surrendered.

Athens gained the upper hand at Sphacteria in 425 BC
In a shocking turn of events, 300 Spartan hoplites encircled by Athenian forces surrendered.
From Wikipedia, Peloponnesian War (opens en.wikipedia.org), as of 2026-08-22.
Brasidas and Cleon were both killed at Amphipolis , and the Peace of Nicias was signed in 421 BCE.

Both Brasidas and Cleon were killed in Athenian efforts to retake Amphipolis
With both city-states exhausted from years of fighting, the Peace of Nicias was signed in 421 BC.
From Wikipedia, Peloponnesian War (opens en.wikipedia.org), as of 2026-08-22.

Sicily and defeat

In 416 BCE, during a truce, Athens took neutral Melos , executed its men and sold its women and children as slaves.

In the summer of 416 BC, during a truce with Sparta, Athens invaded the neutral island of Melos
After the city's fall, the Athenians executed all the adult men, and sold the women and children into slavery.
From Wikipedia, Peloponnesian War (opens en.wikipedia.org), as of 2026-08-22.
The expedition to Sicily against Syracuse (415–413 BCE) ended in defeat and the loss of most of the Athenian navy.

The third phase, the Sicilian Expedition, saw Athens attempt to conquer the Spartan-allied Syracuse. Fought between 415 and 413 BC, the expedition ended in defeat for Athens and the destruction of most of its navy.
From Wikipedia, Peloponnesian War (opens en.wikipedia.org), as of 2026-08-22.
In 405 BCE the Spartan Lysander destroyed the Athenian fleet at Aegospotami ; only 12 ships escaped.

Sparta, led by Lysander, built a Persian-financed fleet to break Athens's naval superiority.
Through cunning strategy, Lysander totally defeated the Athenian fleet, in 405 BC, at the Battle of Aegospotami, destroying 168 ships. Only 12 Athenian ships escaped
From Wikipedia, Peloponnesian War (opens en.wikipedia.org), as of 2026-08-22.
Facing starvation, Athens surrendered on 25 April 404 BCE and lost its walls, its fleet and all its overseas possessions.

Facing starvation and disease from the prolonged siege, Athens surrendered on 25 April 404 BC
The surrender stripped Athens of its walls, its fleet, and all of its overseas possessions.
From Wikipedia, Peloponnesian War (opens en.wikipedia.org), as of 2026-08-22.
Sparta set up the Thirty Tyrants to rule Athens; in 403 BCE Thrasybulus restored democracy .

For a short time, Athens was ruled by the Thirty Tyrants, a reactionary regime set up by Sparta. In 403 BC, the oligarchs were overthrown and a democracy was restored by Thrasybulus.
From Wikipedia, Peloponnesian War (opens en.wikipedia.org), as of 2026-08-22.

How we know

The main source is Thucydides , an Athenian who fought early in the war; his account ends abruptly in 411 BCE.

The main historical source for most of the war is the detailed account in The History of the Peloponnesian War by Thucydides.
An Athenian who fought in the early part of the war, Thucydides was exiled in 423 BC
The main limitation of Thucydides' work is that it is incomplete: the text ends abruptly in 411 BC, seven years before the conclusion of the war.
From Wikipedia, Peloponnesian War (opens en.wikipedia.org), as of 2026-08-22.
Xenophon continued the story in his Hellenica, written about 40 years after the war and generally seen as favourable to Sparta.

The account was continued by Xenophon, a younger contemporary, in the first book of his Hellenica.
he retired to live in Sparta, where he wrote Hellenica around 40 years after the war had ended. His account is generally considered favourable to Sparta.
From Wikipedia, Peloponnesian War (opens en.wikipedia.org), as of 2026-08-22.

Events

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