The Fragile Peace Before the Storm
The fifty years between Xerxes’ retreat from Greece and the outbreak of the Peloponnesian War witnessed constant tension among Greek city-states. During this period, Athens transformed its Delian League into a formidable empire while Sparta remained largely passive – not out of indifference, but due to internal challenges and their traditional reluctance to engage in distant conflicts unless absolutely necessary. This strategic patience would prove temporary as Athenian ambitions grew increasingly bold.
Athens’ imperial expansion followed a clear pattern: first securing naval dominance, then extracting tribute from allies, and finally asserting control over strategic territories. The transformation from liberator to overlord occurred gradually, with each step justified as necessary for collective security against Persia. Meanwhile, Sparta’s alliance system remained more decentralized, reflecting their different social priorities and military traditions.
The Breaking Points: Three Crises That Made War Inevitable
Three flashpoints brought tensions to the boiling point. The Corcyra incident (433 BCE) saw Athens intervene in a conflict between Corinth and its colony Corcyra (modern Corfu), gaining a crucial naval ally while angering Corinth, Sparta’s powerful partner. Next came the Potidaea revolt (432 BCE), where an Athenian tributary city with Corinthian ties rebelled, prompting Athens to lay siege – an act Sparta interpreted as aggression against its alliance system.
Most provocatively, Athens issued the Megarian Decree, barring Megara from Athenian markets and ports. This economic stranglehold struck at Corinth’s regional influence while demonstrating Athens’ ability to weaponize trade. For Sparta’s allies, particularly Corinth, these actions revealed an Athens that could no longer be contained through diplomacy.
Divine Sanctions and Diplomatic Maneuvers
Seeking divine approval before committing to war, Sparta consulted the Oracle at Delphi. The priests’ response – that victory would come if Sparta fought with all its might – provided religious justification. Yet Sparta still convened the Peloponnesian League for a formal vote, demonstrating their leadership style contrasted with Athenian direct democracy.
The Corinthian speech to the assembly became a masterclass in persuasive rhetoric. Their delegates framed the conflict as existential: Athens’ growing power threatened all Greek freedom. Using vivid metaphors (“a tyrant city”), they warned that delay meant certain domination. The speech cleverly appealed to Spartan honor while addressing practical concerns about naval inferiority, proposing innovative solutions like using temple treasures to build a competitive fleet.
The Curse That Haunted Diplomacy
A surprising obstacle emerged from religious curses dating back generations. Sparta demanded Athens expel those “accursed” from the Cylonian affair (7th century BCE), when supplicants were murdered after promised safe passage. Athens countered by citing Spartan impieties, including the killing of helot supplicants at Taenarus and the mysterious death of the regent Pausanias in a temple.
These ancient curses became modern political weapons. When Sparta demanded Pericles’ expulsion (his family being connected to the Cylonian curse), they likely aimed to weaken Athenian leadership rather than genuinely address religious concerns. The reciprocal accusations reveal how Greek states weaponized piety when convenient.
The Final Ultimatum
Sparta’s last embassy reduced demands to three points: lift the siege of Potidaea, grant Aegina autonomy, and repeal the Megarian Decree. But their core message – that peace required “freeing Greece” – struck at Athens’ imperial structure. Pericles’ response, preserved by Thucydides, became a classic defense of empire and resolve.
The great statesman argued that concessions would invite more demands, comparing empire to tyranny – “perhaps wrong to acquire, but dangerous to let go.” His speech balanced confidence in Athenian naval supremacy with sober warnings about avoiding land battles against Sparta’s superior infantry. Most importantly, he framed resistance as maintaining Athens’ honor and legacy.
The Human Factor: Leadership and Miscalculation
Behind these grand strategic calculations stood fascinating individuals. The Spartan king Archidamus advocated caution, understanding Athens’ strengths. The Corinthian delegates skillfully played on Spartan fears. Most crucially, Pericles’ leadership shaped Athenian resolve, though his confidence in limited war proved tragically misplaced.
Modern historians debate whether war was truly inevitable. Some argue economic factors – Athens’ need to control trade routes, Corinth’s commercial rivalry – made conflict unavoidable. Others emphasize psychological factors: Athenian overconfidence after decades of success, Spartan fear of losing prestige. The complex interplay of honor, interest, and misperception created a perfect storm.
The Legacy of Decisions Unmade
When the Peloponnesian League voted overwhelmingly for war in 432 BCE, they set in motion a conflict that would last 27 years, reshape Greece, and end Athens’ golden age. The failure of diplomacy reveals much about ancient Greek politics: the primacy of honor over material interest, the weight given to religious sanctions, and the difficulty of maintaining multi-state alliances.
Thucydides’ account of this pre-war period remains foundational for understanding how democracies and oligarchies make fateful choices. His portrayal of escalating tensions, failed negotiations, and the rhetoric of inevitability still resonates in modern international relations, reminding us how powers can sleepwalk into catastrophic conflicts.