Peloponnesian War Summary

  • Last updated on November 11, 2022

The Peloponnesian War, a military conflict between the two greatest powers of ancient Greece, Athens and Sparta, was also the final stage of a long-standing struggle between conflicting political, economic, and social systems.

Summary of Event

In the late spring of 431 b.c.e., the tensions that had existed between Athens and Sparta since the end of the Greco-Persian War suddenly erupted into open conflict. The resulting war became known as the Peloponnesian War because Sparta’s area of greatest influence was the Peloponnese, the peninsula on which it was located. The causes of the war were long-standing. The Great Peloponnesian War (also known as the First Peloponnesian War; 459-445 b.c.e.), largely a conflict between Athens and Corinth, with Sparta also participating, had ended with a truce between Athens and Sparta, but neither side had abided completely by its terms. Lysander of Sparta Alcibiades of Athens Brasidas of Sparta Nicias of Athens Demosthenes Cleon of Athens Pericles

In 433 b.c.e., Athens defended the island of Corcyra against Corinth and excluded the city of Megara from commerce with any city in the Athenian empire. Both Corinth and Megara were Spartan allies, and the Athenians’ actions were taken as open acts of aggression, provoking a war between the two cities that had long vied for domination in Greece. In May, 431, Athens and Sparta finally erupted into war.

The military leader Pericles developed a strategy intended to win an easy victory for Athens. Pericles avoided direct conflicts with the much larger Spartan land army and took his forces to the sea, where Athens had an advantage. The entire population of Attica, the region in which Athens was located, withdrew behind the Long Walls, a defensive structure that connected the city to its port. Safe behind these defenses, the Athenians allowed the Spartans to invade Attica. The loss of Attic grain caused by this invasion was not a significant problem. The protection of the Long Walls permitted the Athenians to import substantially all the food they needed by sea.

Nevertheless, the crowding that resulted in Athens because of Pericles’ strategy had one effect that the general had not foreseen: the spread of disease. After the first year of the war, a plague erupted in Athens, killing as much as one-quarter of the population. Pericles was fined and not selected as general for the following year. In the intervening period, Pericles himself became ill and died of the plague in the autumn of 429 b.c.e. Without the guidance of Pericles, the Athenians began to take increasingly brutal measures against their adversaries.

In 428 b.c.e., Mitylene, a city on the island of Lesbos, attempted to free itself from the Athenian empire. The Athenians resisted this action and starved the city into submission by May of 427 b.c.e. Back in Athens, the assembly decreed that all Mitylenaean men were to be killed, with the women and children sold into slavery. After a ship had already been dispatched to carry out this decree, the assembly reconvened to examine the severity of its sentence. Cleon of Athens, a politician popular with the masses, argued that the punishment of Mitylene had to be carried out as planned. He described the Athenian empire as a tyranny, saying that the state was now compelled to act like a despot and use terror and cruelty to keep its subjects in check. In the end, Cleon’s arguments failed. The Athenians voted to “lighten” Mitylene’s penalty by executing “only” about one thousand of the rebels, seizing the island’s fleet, and destroying its defensive walls. Within six years, however, the harsh penalties proposed by Cleon would be used against rebel cities as a matter of ordinary policy, without any further opposition from the assembly.

By 425 b.c.e., the Athenians appeared to be winning the Peloponnesian War. Demosthenes (not the famous orator, but an earlier general of the same name) established a stronghold at Pylos on the southwest coast of the Peloponnesian peninsula. When the Athenians could not be dislodged from this base, the Spartans sued for peace. Nicias of Athens—who was often accused of being pro-Spartan—wanted the Athenian assembly to accept this proposal, but he was resisted by Cleon, who argued that Athens should hold out for better terms. As a result of this argument, Cleon was placed in command of the Athenian force on the Peloponnese and arrived in Pylos to discover that the army there was already planning a massive attack against the Spartans. When this attack occurred, the Spartans endured a loss of nearly a third of their troops and then surrendered, providing the Athenians with a group of hostages that included 120 full Spartan citizens. As Cleon had hoped, the Spartans then offered peace without concessions, proposing that Athens be allowed to keep its empire and all of its possessions.

Cleon sought an even greater victory. He suggested an aggressive campaign against the Spartans that would compel them to yield territory. In 424 b.c.e., the Spartan general Brasidas captured an Athenian ally (Amphipolis) in northern Greece through a combination of negotiation and strategy. In 422 b.c.e., in a second battle over Amphipolis, both Cleon and Brasidas were killed. With the death of the leading Athenian opponent to peace, Sparta and Athens signed a treaty in March of 421 b.c.e. This treaty, known as the Peace of Nicias after its leading negotiator, held until the summer of 416 b.c.e., when the Athenians attacked the island of Melos, forcing it to join the empire. When Melos was captured, all men of military age were executed, and all other citizens were enslaved.

In the following year, the Athenians also began a campaign to extend their empire westward into Sicily. The plan proved to be a disaster. Alcibiades of Athens, the former ward of Pericles and one of the Athenian generals sent to Sicily, was recalled just before the battle began on suspicion of having profaned the religious rites of Demeter. On his way back to Athens, Alcibiades slipped his guard and fled to Sparta. Partly because of Alcibiades’ betrayal and partly because of the arrival of the Spartan commander Gylippus, a major portion of the Athenian fleet was destroyed in the campaign. Of a total force of forty thousand, only seven thousand soldiers survived the battle and a subsequent retreat inland. Nicias and Demosthenes were killed. The rest of the troops were imprisoned in a quarry, where the harsh conditions killed many.

Although its economy was nearly ruined, Athens used its limited resources to build additional ships and recruit soldiers. The Spartans also chose a new commander, Lysander, an incorruptible politician who had distinguished himself both as a diplomat and as an admiral. In 405 b.c.e., Lysander captured the Athenian fleet at Aegospotami along the Hellespont. Some 170 ships were seized and four thousand Athenian soldiers were executed after the battle. Lysander then swept the coast of Asia Minor, forcing all Athenians and Athenian supporters to return to Athens. Filled with this excess population and with no means of importing food, Athens was starved out, finally offering unconditional surrender to Sparta in 404 b.c.e.


The terms imposed by the Spartans were relatively mild: Athens had to adopt Sparta’s foreign policy, allow its exiles to return, reduce its fleet to a defensive force of twelve ships, and breach the Long Walls. The defeat of Athens prevented what might otherwise have been a spread of direct democracy throughout much of Greece (and possibly elsewhere in Europe as well). The Peloponnesian War also came to symbolize for many people the conflict between democracy and military oligarchy, freedom and totalitarianism, and passion and control.

Further Reading
  • citation-type="booksimple"

    xlink:type="simple">Forrest, William George Grieve. A History of Sparta, 950-192 b.c. 2d ed. London: Duckworth, 1980. The standard history of Sparta for the general reader; Forrest condenses the Peloponnesian War to a concise account of fewer than twenty pages.
  • citation-type="booksimple"

    xlink:type="simple">Hornblower, Simon. The Greek World, 479-323 b.c. 3d ed. New York: Routledge, 2002. An examination of the rise of Athens and its conflict with Sparta in the Peloponnesian War.
  • citation-type="booksimple"

    xlink:type="simple">McGregor, Malcolm Francis. The Athenians and Their Empire. Vancouver: University of British Columbia Press, 1987. Focuses on the period of Athenian supremacy from the end of the Greco-Persian Wars through the fall of Athens in the closing days of the Peloponnesian War.
  • citation-type="booksimple"

    xlink:type="simple">Powell, Anton. Athens and Sparta: Constructing Greek Political and Social History from 478 b.c. 2d ed. New York: Routledge, 2001. An excellent study of the political and social relationship between Athens and Sparta from 478 b.c.e. onward, with special attention given to the period of the Peloponnesian War.
  • citation-type="booksimple"

    xlink:type="simple">Roisman, Joseph. The General Demosthenes and His Use of Military Surprise. Stuttgart: F. Stiner, 1993. A look at the role of the general Demosthenes in the Peloponnesian War.
  • citation-type="booksimple"

    xlink:type="simple">Wartenberg, Ute. After Marathon: War, Society, and Money in Fifth Century Greece. London: British Museum Press, 1995. This catalog of coins from the collection of the British Museum discusses the Athenians and the Peloponnesian War.
Related Articles in <i>Great Lives from History: Ancient World</i>

Alcibiades of Athens; Pericles. Peloponnesian War (431-404 b.c.e.)

Categories: History