History of the Peloponnesian War

1. The Inevitable Clash of Great Powers

The real cause I consider to be the one which was formally most kept out of sight. The growth of the power of Athens, and the alarm which this inspired in Lacedaemon, made war inevitable.

Underlying tension. The Peloponnesian War was not merely a series of isolated disputes but the inevitable outcome of a fundamental shift in the balance of power in Hellas. Athens, having risen to unprecedented naval and economic strength after the Persian Wars, naturally provoked fear and jealousy in the established land power, Lacedaemon. This deep-seated apprehension was the true engine of the conflict.

Pretexts for war. While the underlying cause was Athens' growing power, specific incidents served as immediate triggers. The dispute over Epidamnus, a Corcyraean colony, drew Corinth into conflict with Corcyra, which then sought Athenian alliance. Similarly, the Athenian siege of Potidaea, a Corinthian colony and Athenian tributary, further inflamed tensions, leading Corinth to accuse Athens of treaty violations at Sparta.

Spartan deliberation. The Lacedaemonians, after hearing complaints from their allies, particularly Corinth and Megara (excluded from Athenian ports), ultimately voted for war. This decision was driven less by the specific grievances and more by their growing fear of Athenian dominance, recognizing that Athens' power had reached a point where it could no longer be ignored without risking their own supremacy.

2. Thucydides' Enduring Historical Method

In fine, I have written my work, not as an essay which is to win the applause of the moment, but as a possession for all time.

Commitment to accuracy. Thucydides meticulously gathered information, relying on eyewitness accounts and his own observations, rather than accepting traditions uncritically. He acknowledged the difficulty of obtaining precise details due to imperfect memory or bias, but strove for the most exact conclusions possible, even if it meant sacrificing "romance" for truth.

Focus on human nature. Beyond mere chronology, Thucydides sought to understand the underlying human motivations—fear, honor, and interest—that drove the actions of states and individuals. He believed that by understanding these constant forces, his history could serve as a guide for interpreting future events, which would inevitably resemble the past.

Speeches as insight. The speeches in his history, while not verbatim, aimed to capture the general sense of what was said and what the occasion demanded. They serve as a crucial tool for revealing the political thought, arguments, and psychological states of the actors, offering a deeper understanding of the conflict's dynamics and the clash of ideologies.

3. Athenian Imperial Ambition and Justification

That empire we acquired by no violent means, but because you were unwilling to prosecute to its conclusion the war against the barbarian, and because the allies attached themselves to us and spontaneously asked us to assume the command.

Post-Persian War rise. Athens' empire began after the Persian Wars when Sparta withdrew from leadership, and the Ionian and Hellespontine allies voluntarily sought Athenian command. This Delian League, initially formed to retaliate against Persia, gradually transformed into an Athenian empire as Athens became more exacting and allies opted to pay tribute instead of furnishing ships.

Justification for rule. The Athenians argued that their empire was a necessity, driven by fear, honor, and interest. They asserted that it was natural for the stronger to rule the weaker, and that their rule, though sometimes perceived as harsh, was more equitable than that of other imperial powers. They also highlighted their crucial role in repelling the Medes.

Maintaining control. Athens maintained its empire by gradually disarming its allies, imposing monetary contributions, and swiftly suppressing revolts. They believed that giving up their empire was unsafe, as any seceding state would fall to Sparta, and that their naval power was essential for their own security and continued influence in Hellas.

4. Contrasting Spartan Caution with Athenian Dynamism

The Athenians are addicted to innovation, and their designs are characterized by swiftness alike in conception and execution; you have a genius for keeping what you have got, accompanied by a total want of invention, and when forced to act you never go far enough.

Clash of temperaments. The Corinthians, in their speech to the Lacedaemonians, sharply contrasted the two leading powers. Athenians were depicted as innovative, adventurous, swift in action, and restless, always seeking new acquisitions. Spartans, conversely, were portrayed as conservative, slow to act, cautious, and focused on preserving what they had.

Strategic implications. This fundamental difference in national character had significant strategic consequences. Athenian dynamism allowed them to adapt and expand, while Spartan deliberation often led to missed opportunities. The Corinthians argued that Sparta's slowness in crushing Athens in its infancy allowed its power to grow unchecked, making the eventual conflict far more challenging.

Military approaches. Athens, a maritime power, relied on its fleet and financial resources, while Sparta, a land power, excelled in heavy infantry. The war would test which approach, and which national character, was better suited to prolonged conflict and the complexities of Hellenic politics.

5. The Corcyraean Revolution: A Descent into Brutality

So bloody was the march of the revolution, and the impression which it made was the greater as it was one of the first to occur.

Internal strife. The revolution in Corcyra began with the return of prisoners released by Corinth, who, under the guise of debt repayment, sought to detach Corcyra from Athens. This led to a violent clash between the oligarchic and democratic factions, escalating into widespread murder and chaos.

Breakdown of norms. The civil war saw a complete perversion of traditional values and language. Reckless audacity was praised as courage, prudent hesitation condemned as cowardice, and moderation seen as unmanliness. Oaths and agreements lost their meaning, replaced by treachery and ruthless self-interest, as each side sought to destroy the other.

Universal pattern. Thucydides presented the Corcyraean revolution as a microcosm of the broader Hellenic world, where similar struggles between popular and oligarchic factions erupted. He observed that war, by disrupting daily life and creating extreme necessities, stripped away civility and revealed the darkest aspects of human nature, leading to ever-greater excesses.

6. The Devastating Impact of the Athenian Plague

Nor was this the only form of lawless extravagance which owed its origin to the plague. Men now coolly ventured on what they had formerly done in a corner, and not just as they pleased, seeing the rapid transitions produced by persons in prosperity suddenly dying and those who before had nothing succeeding to their property.

Unprecedented calamity. The plague struck Athens during the second Peloponnesian invasion, causing immense mortality and widespread panic. Its symptoms were horrific and baffling to physicians, who often died themselves. The disease spread rapidly, exacerbated by the crowded conditions within the city due to the rural population seeking refuge behind the Long Walls.

Social and moral decay. The overwhelming nature of the disaster led to a breakdown of social norms and religious belief. People abandoned traditional burial rites, indulged in immediate pleasures, and disregarded laws, believing that a far greater sentence of death already hung over them. This moral decay was a direct consequence of the plague's indiscriminate and terrifying power.

Strategic implications. The plague severely weakened Athens, killing a significant portion of its population, including Pericles. It undermined morale and led to public discontent with Pericles' leadership. Despite this, the Athenians, though suffering, continued their war efforts, demonstrating their resilience even in the face of unforeseen catastrophe.

7. Pericles' Strategic Vision and Leadership

In short, what was nominally a democracy became in his hands government by the first citizen.

Guiding the democracy. Pericles, recognized as Athens' foremost statesman, exercised immense influence over the Athenian democracy. His authority stemmed from his intellect, integrity, and ability to articulate a clear strategic vision, allowing him to lead the populace rather than be led by their whims.

Wartime strategy. Pericles advocated a defensive strategy: avoid land battles with the Peloponnesians, rely on the superior Athenian navy, and endure the ravaging of Attica. He urged Athenians to focus on their maritime empire, which provided revenue and allowed them to outlast their land-based adversaries, while keeping a tight rein on their allies.

Foresight and legacy. Pericles foresaw the long and arduous nature of the war, warning against over-ambition and internal divisions. His death early in the war, combined with the plague, left Athens vulnerable to less capable successors who, driven by private ambition, would make critical blunders, ultimately leading to the Sicilian disaster.

8. The Catastrophic Sicilian Expedition

This was the greatest Hellenic achievement of any in thig war, or, in my opinion, in Hellenic history; at once most glorious to the victors, and most calamitous to the conquered.

Ambitious undertaking. Despite Nicias's warnings about the scale and difficulty, Athens, swayed by Alcibiades's charisma and the allure of vast wealth and empire, launched a massive expedition to conquer Sicily. Their stated goal was to aid allies, but the true ambition was to subdue the entire island, particularly Syracuse, and then use its resources to conquer Peloponnese.

Initial setbacks and miscalculations. The expedition faced immediate challenges, including the Egestaeans' false promises of wealth and the refusal of some Italian cities to join. Lamachus advocated a swift, decisive strike against Syracuse, but Nicias's caution and the army's initial inaction allowed the Syracusans to prepare and receive Spartan aid under Gylippus.

Ultimate defeat. The Athenian siege of Syracuse was met with determined resistance, strategic counter-fortifications, and eventually, naval defeats in the Great Harbour. Trapped and demoralized, the Athenian army's attempt to retreat by land ended in a catastrophic rout and annihilation, marking the single greatest disaster for any Hellenic force in the war.

9. Alcibiades: Charismatic Exile and Strategic Advisor

I am an outlaw from the iniquity of those who drove me forth, not, if you will be guided by me, from your service; my worst enemies are not you who only harmed your foes, but they who forced their friends to become enemies; and love of country is what I do not feel when I am wronged, but what I felt when secure in my rights as a citizen.

Divisive figure. Alcibiades, a brilliant but controversial Athenian general, was recalled from Sicily to face charges of impiety and conspiracy. Fearing conviction, he defected to Sparta, where he became a crucial advisor to Athens' enemies.

Strategic counsel to Sparta. Alcibiades urged the Lacedaemonians to fortify Decelea in Attica, providing a permanent base for harassing Athens, and to send immediate aid to Syracuse. He argued that these actions would cripple Athens' resources and morale, shifting the balance of the war. His advice proved highly effective, causing immense damage to Athens.

Shifting loyalties. Alcibiades later fell out of favor with the Spartans and sought to return to Athens, leveraging his supposed influence with the Persian satrap Tissaphernes. His complex intrigues and shifting allegiances highlight the personal ambitions and political maneuvering that often overshadowed broader strategic goals during the war.

10. The Oligarchic Coup and Democratic Resistance

Indeed at Samos the question of the oligarchy had already entered upon a new phase, the following events having taken place just at the time that the Four Hundred were conspiring.

Internal Athenian turmoil. While the Sicilian expedition was underway, a conspiracy to overthrow the Athenian democracy gained momentum. Led by figures like Pisander and Antiphon, the oligarchs promised Persian aid and a more stable government, appealing to citizens weary of war and heavy taxation.

The Four Hundred. The conspirators successfully established an oligarchy of Four Hundred, abolishing democratic institutions and ruling by force. They sought peace with Sparta, believing a more moderate government would be more trustworthy to the Lacedaemonians.

Samos's democratic stand. Crucially, the Athenian army and fleet at Samos, largely composed of common citizens, resisted the oligarchic coup. They maintained their democratic government, recalled Alcibiades, and vowed to continue the war against Sparta and the Four Hundred, becoming a powerful counter-force that eventually led to the downfall of the oligarchy in Athens.

11. The Enduring Laws of Human Nature in Conflict

Of the gods we believe, and of men we know, that by a necessary law of their nature they rule wherever they can.

Universal motivations. Thucydides repeatedly illustrates that human actions in war are driven by constant, predictable forces: fear, self-interest, and honor. States, like individuals, seek to expand their power when strong and defend themselves when weak, often rationalizing their actions with claims of justice or necessity.

Power dynamics. The narrative consistently demonstrates that "right, as the world goes, is only in question between equals in power, while the strong do what they can and the weak suffer what they must." This stark realism, articulated in the Melian Dialogue, underscores the brutal logic of international relations where might often dictates justice.

Cycles of conflict. The war itself, with its shifting alliances, betrayals, and unforeseen disasters (like the plague), reveals the inherent unpredictability of human affairs. Despite careful planning, chance plays a significant role, and the pursuit of power often leads to unintended and devastating consequences, perpetuating cycles of conflict and suffering.

Last updated: January 16, 2026