Peloponnesian War


The Peloponnesian War was a Greek conflict fought by the Peloponnesian League, led by Sparta, and the Athenian Empire. The war lasted 27 years, from 431 to 404 b.c.e., with a six-year truce in the middle, and ended with an Athenian surrender.

The war involved much of the Mediterranean world, and large-scale campaigns and intense fighting took place from the coast of Asia Minor to Sicily and from the Hellespont and Thrace to Rhodes. The conflict is often viewed as an archetypal case of warfare between a commercial democracy and an agricultural aristocracy and of warfare between maritime and continental superpowers.

Thucydides, an Athenian general and historian, documented the events of the conflict in his History of the Peloponnesian War. It was, consequently, the first war in history to be recorded by an eyewitness and talented historian.


Historians posit multiple causes for the Peloponnesian War. Thucydides argued that the underlying cause of the war was Sparta’s fear of growing Athenian power during the fifth century b.c.e. This perspective is supported by the well-documented rise and power of Athens in the 50 years prior to the outbreak of the war.

After a coalition of Greek cities, which included both Athens and Sparta, defeated a Persian invasion of Greece, several of these states formed a more formal coalition called the Delian League in 478 b.c.e.

The purpose of the league was to enhance economic ties and establish a navy to deter further Persian aggression. Athens was afforded leadership of the league, which gave it control over the league’s treasury.

Through a series of political maneuvers by Athens in the decades following the creation of the league, the coalition was transformed into an Athenian-dominated empire. After 445 b.c.e. the Athenian leader Pericles began consolidating Athenian resources and expanded the Athenian navy to such an extent that its power was without equal in Greece.

In 433 b.c.e. Pericles forged an alliance with another strong naval power, Corcyra, which was the chief rival of Sparta’s ally Corinth. These actions greatly enhanced Athenian power and, conversely, weakened the power of other Greek cities, particularly those who were members of Sparta’s Peloponnesian League.

Athenian naval dominance allowed them to control virtually all sea trade, which threatened the supply of food from Sicily to cities in the Peloponnese, including Sparta. Furthermore, Athens boycotted cities that resisted its growing power, including Sparta’s ally Megara.

It was on these grounds that Corinth demanded that Sparta take up arms against the Athenian empire. The appeal was backed by Megara—nearly ruined by Pericles’s economic boycott—and by Aegina, a reluctant member of the Athenian Empire.

The actual outbreak of fighting in 431 b.c.e. sprung from Sparta’s desire to capitalize on a moment of Athenian weakness. The city of Potidaea, a subject member of the Athenian empire, revolted in the spring of 432 b.c.e. The rebel city held out until the winter of 430 b.c.e. and its blockade by Athens meant a constant drain on Athenian naval and military resources.

Sparta’s leaders were so confident of a quick and easy victory over Athens that they refused an offer of arbitration made by Pericles. Instead, Sparta issued an ultimatum that would have practically destroyed Athens’s imperial power. Pericles urged his people to refuse, and Sparta declared war.

Hostilities began in 431 b.c.e. with a Theban attack on Athens’s ally, Platea, and 80 days later by a Peloponnesian invasion of Attica. Now capable of invading Attica through the Megarid, Sparta did so numerous times through 425 b.c.e. Sparta only curtailed these attacks when Athens captured a number of Spartan hoplites and held them hostage.

At first, on Pericles’ advice, the Athenians employed a defensive strategy, taking refuge inside the walls surrounding the city and the port of Piraeus, and limiting offensive operations to brief cavalry missions, raids into the Peloponnese, and a series of invasions of the Megarid.

However, following Pericles’ death in 429 b.c.e. and the failed Mytilenean revolt in 427 b.c.e., Athens adopted a more offensive strategy. This included establishing bases on the Peloponnesian coast. Athens also attempted to force Boeotia’s surrender through a pair of elaborate invasions, the second of which ended in a stunning defeat at Delium in 424 b.c.e.

The Spartans marched overland to Chalcidice and, through persuasion and threats, convinced a number of Athens’s allies to join the Spartan cause. Brasidas’s own death in battle outside Amphipolis in 422 b.c.e. and that of the Athenian demagogue Cleon led to the conclusion of a temporary peace.

The peace was unsatisfactory to many of Sparta’s allies, and the Athenian Alcibiades created an anti-Spartan coalition in the Peloponnese. At the Battle of Mantineia in 418 b.c.e. the Spartans were victorious.

With Sparta’s position in the Peloponnese once more secure, Alcibiades turned elsewhere for a field in which to exercise his talents, and in 415 b.c.e. Athens sent an expedition to Sicily, where he served as one of three commanders.

Historians believe it was either a preemptive strike to prevent Syracuse from conquering the island and providing military aid to the Spartan-led coalition in the Peloponnese, or simply to bolster a long-held Athenian interest in the island. Regardless, the expedition ended in disaster in 413 b.c.e. During the siege Alcibiades was recalled to Athens to face charges of sacrilege but fled to Sparta rather than stand trial.

Peloponnesian sea battle
Peloponnesian sea battle

In the meantime, mainland Greece had once more slipped into open warfare. The Athenians raided the Peloponnese, while the Spartans invaded Attica in 413 b.c.e. and seized a strategically important base at Decelea in the foothills north of Athens. However, the loss of so many Athenian ships and trained crews in Sicily changed the nature of the war.

The Spartans understood that the way to defeat Athens at sea was to win control of the Hellespont and Propontis, thus choking off essential supplies to the struggling city. By 411 b.c.e. the conflict became increasingly focused on that area of Greece. Athens was hampered by internal problems, culminating in the overthrow of the democracy in June 411 b.c.e.

The oligarchs who seized power were unable to reconcile the Athenian fleet at Samos to their rule, and in September they were overthrown. Initially, only a limited form of democracy was restored, but the victory near Cyzicus in 410 b.c.e. led to the restoration of the old system.

Alcibiades returned to Athens by way of Persia, and was elected once again as commander of the Athenian forces. He arrived in time to take part in the victory off Abydos and another near Cyzicus the subsequent year.

Following additional success in the north, such as the recovery of Byzantium in 408 b.c.e., Alcibiades returned to Athens in triumph in 407 b.c.e. and was awarded supreme command of the Athenian navy on the west coast of Asia Minor.

Lysander successfully attacked one of Alcibiades’ subordinates while the Athenian commander was absent. The furious Athenians dismissed Alcibiades, who fled to Thrace. Lysander ultimately achieved a victory at Aegospotami in 405 b.c.e.

As a result, while Athens valiantly held out until the spring of 404 b.c.e., it succumbed to economic starvation imposed by overwhelming Spartan forces and surrendered.

Ultimately, despite some daring strategies, the Peloponnesian War was a war of resources. The Spartans were victorious because Persian gold enabled them to build more ships and to purchase more mercenaries than Athens could.

However, Sparta also understood from the outset that Athens, as a maritime power that depended on port trade, would have to be defeated at sea. Conversely, the Athenians do not appear to have understood that Sparta, as a land power, could only be defeated on land.