Athenian Invasion of Sicily Summary

  • Last updated on November 11, 2022

The Athenian invasion of Sicily failed when the invasion force sent by Athens to Sicily was totally destroyed, setting Athens on its course to inevitable defeat in the Peloponnesian War.

Summary of Event

Following the successful conclusion of the series of wars with Persia during the sixth century b.c.e., the Greek city-states gradually settled into a system of conflicting alliances headed by Athens on the one hand and Sparta on the other, or they tried to maintain neutrality between these two great powers. In 477 b.c.e., Athens became head of the Delian League, supposedly a purely defensive association of some 150 Greek city-states. Within fifty years, the Delian League had grown to encompass more than 250 city-states and was, for all practical purposes, the Athenian Empire, with all league riches flowing into Athens and with Athens setting league foreign policy. Nicias of Athens Alcibiades of Athens Gylippus Demosthenes (d. 413 b.c.e.)

Sparta, Athens’ major Greek rival, watched its northern neighbor grow steadily more powerful, especially at sea, where the Spartans were weakest. According to the early historian Thucydides, it was this fear of Athenian expansion that led to the outbreak of the Peloponnesian War in 431 b.c.e. It would last, with several interruptions caused by uneasy truces that pretended to be peace, until the final and apparently utter defeat of Athens in 404 b.c.e. One of the factors that led directly to the downfall of Athens was the disaster that overtook its expedition against the city of Syracuse, on the island of Sicily, in 415-413 b.c.e.

The first phase of the war, known as the Archidamian War for the name of the Spartan king who began it, ended inconclusively in 421 b.c.e. The years from 421 through 415 b.c.e. were known as the Peace of Nicias, for Nicias, the Athenian leader who negotiated a treaty with the Spartans. In Athens, the young and brilliant but unscrupulous Alcibiades, a ward of the great Athenian leader Pericles, urged a renewal of the conflict and an invasion of Sicily. He claimed this invasion would cut off Sparta’s vital supply of Sicilian wheat. It is also thought that Alcibiades may have dreamed of further conquests of southern Italy or Carthage.

Although the invasion plan was vigorously resisted by Nicias of Athens and other conservative leaders, it was enormously popular, and, in June, 415 b.c.e., the Athenians launched what was then an enormous fleet of at least 134 warships carrying between 5,000 and 6,500 heavy infantry (hoplites) and light armed troops. In joint command of the expedition were Alcibiades, Nicias, and Lamachus, the last more a professional soldier than a politician.

Just before the armada sailed (some sources say the very night before), a number of religious statues throughout Athens were mutilated. Because these Herms, as they were known, were sacred to Hermes, the god of travel, the act could be seen either as a bad omen or as a deliberate sacrilege; in either event, considerable suspicion fell on Alcibiades, largely because of his scandalous past, which included participation in mocking celebrations of some of the Greeks’ most solemn religious mysteries. Alcibiades was recalled after the fleet had sailed. Fearing for his life, he fled to Sparta and urged a strong defense of Syracuse and a prompt attack on Athens.

The Athenians are defeated in the Battle of Syracuse.

(F. R. Niglutsch)

In the absence of Alcibiades, the Athenian expedition sailed on and landed in Sicily. Lamachus urged an immediate attack on Syracuse, which might well have carried the city, but Nicias preferred caution. When Lamachus was killed in an early skirmish, Nicias procrastinated and the campaigning season of 415 b.c.e. ended with Syracuse scarcely damaged. The Athenians were forced to withdraw into winter quarters, while the Syracusans appealed for and received help from their mother city of Corinth and its ally Sparta. The Spartans sent one contingent under Gylippus and the Corinthians another under Gongylus.

In 414 b.c.e., Athenian reinforcements arrived in Sicily, and Nicias pressed the Siege of Syracuse, a strong, walled city built on a peninsula that separates a large bay, the Grand Harbor, from the sea. The Athenians seized part of the Grand Harbor, fortified it, and blockaded the city by the sea, hoping by building a wall across the landward end of the peninsula to isolate Syracuse completely and force its surrender through lack of food. Lacking a siege train of battering rams, catapults, and similar weapons, the Athenians had no choice but to attempt the long and arduous process of starving out their opponents—or to have the city betrayed by a faction within its walls. Starvation or betrayal were, in fact, the typical fashion in which sieges were conducted during classical times because a walled city such as Syracuse was, for all practical purposes, invulnerable to assault. After months of inaction, and at the moment when the Athenian strategy seemed about to force the city’s surrender, Gongylus slipped inside the city to report Gylippus’s approach with relief forces. Gylippus’s strategy was to extend a counterwall from Syracuse at right angles to Nicias’s wall and head off its completion. During the summer, fierce combat ranged around the ends of the two walls. By a narrow margin, Gylippus carried his fortifications past those of Nicias and thus frustrated the Athenian offensive. In the autumn, operations stalled, and Nicias asked for reinforcements.

During the winter of 414-413 b.c.e., although under Spartan attack on the Greek mainland, the Athenians dispatched seventy-three additional triremes and five thousand hoplites under the command of Demosthenes. Their arrival barely restored the balance in favor of the Athenians. Fresh naval forces had reached Syracuse from the Peloponnesus and parts of Sicily. The Syracusans had made a bid for victory, and in June and July, 413 b.c.e., they had won a series of naval actions in the Grand Harbor. It was at this point that Demosthenes had arrived, reestablished Athenian naval supremacy, and dashed Syracusan hopes.

Demosthenes and Nicias next decided to capture Gylippus’s counterwall to retrieve gains made in the campaign of the year before. The Athenian army went forward by night and came extremely close to success, but in the darkness, it lost cohesion and was repulsed. Demosthenes promptly advised Nicias to begin immediate withdrawal by sea, but once more Nicias delayed, believing an eclipse of the moon an omen against evacuation. The Syracusans then resumed their naval offensive and, in September, defeated the Athenian fleet in a great battle in the Grand Harbor, compelling Nicias to resort to the forlorn hope of escaping by land. Complete disaster followed. The Syracusan cavalry and light troops harried their enemy and wore them down under a hail of missiles until Nicias surrendered. The Syracusans executed both Nicias and Demosthenes and imprisoned their men in stone quarries for months. Those who did not die under these conditions were sold into slavery.


This military defeat of Athens marked the beginning of the end for the city’s struggle in the Peloponnesian War, primarily because it struck at Athens’ political solidarity. At first enthusiastically united behind Alcibiades’ scheme, the city was devastated first by his defection to the Spartans and then by the complete disaster that overtook the bulk of its relatively limited armed forces. Athens experienced a crisis of confidence from which it never fully recovered.

Although the Sicilian disaster encouraged some revolts within the Athenian Empire and lured Persia into an alliance with Sparta, its main effect—and Alcibiades’ enduring legacy—was to sow distrust and dissension within Athens. It was this internal disarray, which brought distrust to its citizens and timidity to its military commanders, that led to its eventual collapse and final surrender in 404 b.c.e.

Further Reading
  • citation-type="booksimple"

    xlink:type="simple">Ellis, Walter M. Alcibiades. New York: Routledge, 1989. A brief but penetrating study of the Athenian who, almost single-handedly, convinced his native city to embark upon its most dangerous and ultimately disastrous adventure during the long war with Sparta.
  • 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">Kagan, Donald. The Peace of Nicias and the Sicilian Expedition. Ithaca, N.Y.: Cornell University Press, 1981. The best, most extensive and most scholarly modern treatment of the subject, exhaustive in its scope but exhilarating in its narrative. Kagan places the events into their wider historical perspective while maintaining the vividness of an almost firsthand account.
  • 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">Strauss, Barry S., and Josiah Ober. The Anatomy of Error: Ancient Military Disasters and Their Lessons for Modern Strategists. New York: St. Martin’s Press, 1990. In addition to providing a brief but clear explanation of what happened, Strauss and Ober explain in more detail why the Athenian expedition met such a disastrous fate—and indeed, why the entire war resulted in an Athenian defeat.
  • citation-type="booksimple"

    xlink:type="simple">Thucydides. The Peloponnesian War. Translated by Richard Crawley. Edited by Robert B. Strassler, with an introduction by Victor Davis Hanson. New York: Simon and Schuster, 1998. The definitive source for the Sicilian expedition are books 6 and 7 of Thucydides’ history of the war.Contains maps, appendices, and index.
Related Articles in <i>Great Lives from History: Ancient World</i>

Alcibiades of Athens; Thucydides. Sicily, Athenian invasion of Athenian Empire;invasion of Sicily

Categories: History