The Peloponnesian War (431-404 BC)

The Thebans, allies of Sparta, launch a surprise attack on the Athenian-allied town of Plataea, triggering the start of the Peloponnesian War. Sparta's King Archidamus II invades Attica, the region surrounding Athens, beginning the first phase known as the Archidamian War (431-421 BC).

Pericles delivers his famous Funeral Oration honoring the Athenian war dead. The speech, recorded by Thucydides, becomes one of history's most celebrated defenses of democracy, celebrating Athenian values of freedom, equality, and civic duty. It sets the ideological tone for the Athenian war effort.

Location: Athens, Greece

A devastating plague breaks out in overcrowded Athens, where the population has taken refuge behind the Long Walls. The disease kills roughly one-third to two-thirds of the population over three years, including Pericles in 429 BC. The plague destroys Athenian morale and manpower, and is a major factor in Athens' eventual defeat.

Location: Athens, Greece

The Athenian general Demosthenes outmaneuvers the Spartans at Pylos and traps 300 Spartan hoplites on the island of Sphacteria. After weeks of stalemate, Cleon arrives with reinforcements and secures their surrender — a shocking blow to the myth of Spartan invincibility. The Spartans are held hostage in Athens.

Location: Pylos, Messenia, Greece

The Spartan general Brasidas marches an army through the length of Greece and captures the Athenian colony of Amphipolis in Thrace, which controls nearby silver mines crucial to Athens' war funding. The historian Thucydides, then an Athenian general, is exiled for failing to defend the city — and begins writing his history of the war.

Location: Amphipolis, Thrace

After the death of the war hawks Cleon and Brasidas at the Battle of Amphipolis, Sparta and Athens sign the Peace of Nicias, a fifty-year truce. The peace lasts only six years, marked by constant skirmishes and proxy conflicts. Both sides use the interlude to rebuild their forces.

Location: Greece

Sparta defeats the Argive-Athenian alliance at the Battle of Mantinea, the largest land battle within Greece during the war. The victory restores Spartan hegemony over the Peloponnese and rescues Sparta from the brink of strategic defeat. The democratic alliance is broken up.

Location: Mantinea, Arcadia, Greece

During a truce with Sparta, Athens invades the neutral island of Melos. Thucydides records the Melian Dialogue — a ruthless negotiation where Athenians argue that "the strong do what they can and the weak suffer what they must." After Melos refuses to surrender, Athens executes all adult men and enslaves the women and children.

Location: Melos, Aegean Sea

Athens launches the largest expedition in its history — over 100 ships and 5,000 troops — to conquer Syracuse in Sicily. The ambitious campaign is championed by Alcibiades, who defects to Sparta when recalled for trial. Under Nicias, the expedition becomes a catastrophic disaster: the entire fleet is destroyed, and the army is annihilated or enslaved.

Location: Syracuse, Sicily

On the advice of Alcibiades, Sparta fortifies Decelea in Attica, establishing a permanent garrison that prevents Athens from using its land year-round. The disruption of the nearby silver mines causes 20,000 Athenian slaves to flee. Athens is forced to import all supplies by sea, straining its treasury and triggering revolts among its subject allies.

Location: Decelea, Attica, Greece

Sparta signs a treaty with the Achaemenid Persian Empire, exchanging recognition of Persian control over Greek cities in Asia Minor for financial support to build a fleet. The Persian gold allows Sparta to challenge Athens' naval supremacy for the first time in the war.

Athens wins a major naval victory at Arginusae, destroying 70 Spartan ships. However, a storm prevents the rescue of survivors, and the Athenian generals are recalled to stand trial. In a notorious episode of Athenian democracy, the generals are executed for failing to recover the dead — a decision that cripples Athens' military leadership.

Location: Arginusae Islands, near Lesbos

The Spartan admiral Lysander, commanding a Persian-funded fleet, catches the Athenian navy beached at Aegospotami in the Hellespont. The Spartans capture or destroy nearly the entire Athenian fleet of 180 ships, killing thousands of sailors. The victory ends Athens' ability to project naval power.

Location: Aegospotami, Hellespont (modern Dardanelles)

After a months-long siege by land and sea, Athens surrenders in April 404 BC. The Long Walls connecting Athens to Piraeus are demolished to the music of flute-girls. Athens is forced to give up its fleet (except 12 ships), its empire, and its democracy. The Thirty Tyrants, a pro-Spartan oligarchy, are installed. The Peloponnesian War ends after 27 years.

Location: Athens, Greece