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Mediterranean Chronology

The Peloponnesian War Begins

431 BC


The Peloponnesian War (431-404 BC) was a territorial, economic, and political conflict between the Spartan-led Peloponnesian league and the Athenian-led Delian League. While the war began with minor conflicts of allegiances in two expanding city-states, it inflamed a struggle for power between the two dueling leagues.

Prior to the outbreak of the war, the Delian League formed following the end of the Persian wars (479 BC). Athens convinced neighboring city-states that Persia was still a threat, and that unity was the best option for their own protection. To continue their expansion through the incorporation of other city-states, Athens incited revolts in hopes of de-stabilizing those isolated city-state governments whose allegiance they sought. The Athenian government system was very strong at this time and offered many levels of stability for the weaker city-states, particularly economic and political. Due to already established Athenian leadership of the League, it was decided that the Parthenon would become the "bank" to which other city-states paid dues. This added wealth only helped to increase the dominance of Athens in the region. The democratic system in place in Athens served as a political model for other city-states. Representatives from each city-state within the League gathered in Athens to decide policy.

Back to Peloponnesian War Chronology

Sparta led the Peloponnesian league in response to the Delian league. Sparta's politics and social systems were very stable and militaristic. They used powers of persuasion in response to Athens and they convinced other city-states to join them. Sparta commanded a very large infantry but somewhat weaker navy than the Delian league. The Peloponnesian league felt threatened by the Athenian dominance of the area, so they built up their league by recruiting city-states for alliance with their League.

The breakpoint of the war occurred in Epidamnus, a colony founded by the city-state Corcyra. When Epidamnus started having conflicts with neighboring city-states they pleaded with Corcyra for aid. When Corcyra ignored their pleas, Epidamnus appealed to Corinth for help and Corinth agreed. Corcyra did not like the fact that they made an alliance, so a battle broke out. Corcyra started winning and soon both the city-states pleaded to Athens for help. Athens decides following deliberations in their Assembly to help out Corcyra in order to gain naval strength. . They also wanted to protect their treaty with the Peloponnesian league, so they made their alliance with Corcyra a defensive one.  They made a deal that they would only help Corcyra out if Corcyra were being attacked on their home territory. Despite the new alliance, Corinth again attacked Corcyra, and more fighting ensued.

Furthermore, there was a separate yet related conflict in the city-state of Potidaea. This city-state was formally allied to Peloponnesian League as a colony of Corinth, but they paid tribute to Athens. Corinth and other individuals within the Peloponnesian League incited revolts in Potidaea to help weaken Athenian strength in the area and to reclaim lost power. Corinth claimed Athens was breaking the Treaty that had been established. When Athens' military and navy arrived at Potidaea and found the city in revolt, they subsequently besieged the city. The fighting broke out, and due to Corinthian alliances with Sparta in the Peloponnesian league and the conflicts of these two city-states, Sparta's military dominance helped eventually defeat Athens.

The outbreak of the war began with seemingly minor conflicts, but resulted in a war that would shift the balance of powers forever in Greek society. It began in colonies, one outside of the leagues and in a colony with shifted allegiances, and through various appeals and alliances, both major powers were drawn into war.



Ancient Greece: The Peloponnesian War

Ancient History Sourcebook: 11th Britannica: Delian League

Historic Atlas Resource - Europe

Map courtesy of OSSHE Historical and Cultural Atlas Resource.  Used by Permission.


Kagan, Donald, The Outbreak of the Peloponnesian War, (Ithaca: Cornell University Press, 1969)

Ste. Croix, G.E.M. de, The Origins of the Peloponnesian War, (Ithaca: Cornell University Press, 1972)

Strauss, Barry S, Father and Sons in Athens: Ideology and Society in the Era of the Peloponnesian War, (Princeton: Princeton University Press, 1993)

Sullivan, Richard, A Short History of Western Civilization, (New York: McGraw-Hill, 1994)

Thucydides, The Complete Works of Thucydides: The Peloponnesian War, (New York: The Modern Library, 1934).

Edited by: Adam Moore
Researched by: Dan Warren
Written by: Nathan Stockamp
March 16, 2000

Text copyright 2000 by ThenAgain. All rights reserved.

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