The Peloponnesian War was the most important civil war in Greek history, involving almost the entire Greek world and having a profound impact on ancient Greece and even history itself. The two warring parties were the Delian League led by Athens and the Peloponnesian League led by Sparta. The war lasted from 431 BC to 404 BC, during which the two sides had several truces, but Sparta eventually won. This article will review the roots, key processes and consequences of this war.

Root causes of conflict

The background of the war was complex and varied, mainly involving three aspects: economy, politics and religion. Economically, trade competition among Greek city-states intensified, especially the conflict of interests between Athens, Corinth and Megara. The two sides competed for the markets in the west (Italy, Sicily) and the northeast (Macedonia, Thrace, and the Black Sea coastal areas), and Corfu, as an important port on the route to Italy, became the focus of competition between the two sides. Politically, the struggle between Sparta and Athens intensified, mainly centered on the conflict between the democrats and the aristocratic groups in the Greek city-states. Sparta supported the aristocratic groups and the oligarchy, while Athens actively supported the democrats. In addition, religious differences also exacerbated the tension between the two sides to a certain extent. 

War Introduction

The Peloponnesian War was one of the largest and most far-reaching wars in ancient Greek history. This war not only caused a large number of casualties and the destruction of city-states, but also shook the foundation of Greek civilization and created conditions for the rise of Macedonia. 

Archidamus War (431-421 BC)

In 431 BC, Thebes suddenly attacked Plataea, which completely ignited the powder keg between Athens and Sparta. King Archidamas of Sparta immediately led his army into Attica, and the Peloponnesian War officially began. On the Athenian side, under the command of leader Pericles, the rural residents were moved to the city, and relying on the powerful navy, they launched raids at sea while blocking the opponent’s trade routes.

In 425 BC, Athens won the Battle of Pylos and captured a large number of Spartan heavy infantry; in 424 BC, the Spartan general Brasidas captured Amphipolis, and the famous Athenian general Thucydides was exiled for failing to rescue in time.

In 421 BC, the two sides signed the Treaty of Nicias, declaring a fifty-year ceasefire, but the treaty did not resolve the core contradictions, and conflicts between the two allies continued. 

Sicilian Expedition (415-413 BC)

Under the instigation of Alcibiades and other war advocates, the Athenian Citizens Assembly decided to launch an expedition to Syracuse in Sicily in an attempt to control western Greece. Although Nicias opposed the expedition, he was still appointed as one of the commanders. 

As soon as the Athenian fleet arrived in Sicily, a big problem arose. The army was full of internal conflicts, and with Syracuse and Sparta joining forces to defend, the Athenian army soon fell into a stalemate. In 413 BC, the Athenian navy was defeated in the Battle of the Grand Harbor, and the remaining troops were annihilated during the retreat, and a large number of soldiers were reduced to slavery. This expedition caused Athens to lose most of its elite troops and fleet, and its national strength was seriously weakened. 

Dekelian War (413-404 BC)

After the Battle of Sicily, Sparta had always had the upper hand. In 405 BC, the Spartan navy besieged the Hellespont and annihilated the Athenian navy in the Battle of the Aries. Afterwards, the two sides signed a contract that stipulated the dissolution of the Athenian Maritime Alliance, the Athenians destroyed their own defense facilities, and allowed all exiles to return home. Thus, the Peloponnesian War ended. 

Aftermath of the Peloponnesian War

The war severely damaged the vitality of the Greek city-states, causing a sharp decline in population and economic collapse. Athens lost its maritime hegemony and suffered a severe blow to democracy. Although it was able to recover later, it could not regain its former glory. Although Sparta became the hegemon of Greece, its internal contradictions were exposed by the war, and the conflict between the military aristocracy and the civilians intensified, and its hegemonic status could not be maintained for long. City-states such as Corinth and Thebes rose after the war, and the Greek city-states fell into a long-term power struggle and internal friction. 

The Peloponnesian War weakened the overall strength of the Greek city-states, allowing Macedonia in the north to rise. In the 4th century BC, Macedonian King Philip II and his son Alexander the Great took advantage of the division of the Greek city-states to gradually conquer Greece and launched Alexander’s Eastern Expedition, spreading Greek culture to a wider area. The Greek Classical Age ended and the Hellenistic Age began. This war not only changed the historical direction of ancient Greece, but also had a profound impact on the development trajectory of Western civilization.