The Aftermath of the Ten Years’ War
The conclusion of the Ten Years’ War between Athens and Sparta in 421 BCE marked a pivotal moment in Greek history, though the peace proved more fragile than enduring. Under the leadership of Alcaeus in Athens and Pleistolas in Sparta, the two great powers had signed both a peace treaty and a defensive alliance. This agreement theoretically brought peace to those city-states that accepted its terms, yet simmering tensions and competing interests would soon undermine this hard-won stability.
The peace settlement created an uneasy balance of power across the Greek world. While Athens and Sparta had temporarily ceased their direct hostilities, the underlying causes of their conflict remained unresolved. Smaller states found themselves caught between these competing spheres of influence, forced to navigate complex diplomatic waters where allegiances could shift with the political winds. The treaty’s provisions, particularly those regarding territorial exchanges and prisoner releases, would become sources of ongoing friction.
Challenges to the Peace Agreement
Almost immediately after the treaty’s ratification, challenges emerged from unexpected quarters. Corinth and several Peloponnesian city-states actively worked to undermine the agreements, viewing them as detrimental to their own interests. These dissenting voices found fertile ground among Sparta’s allies, where resentment against Spartan leadership had been growing. The Corinthians, in particular, felt betrayed by Sparta’s willingness to make peace with their Athenian rivals without addressing Corinthian grievances.
Meanwhile, Sparta itself began to harbor suspicions toward Athens. Despite six years and ten months without direct invasions of each other’s territories, both powers continued to wage proxy wars and engage in hostilities through their allies. These indirect conflicts gradually eroded trust, with each side accusing the other of failing to fulfill treaty obligations. The peace, though formally intact, was becoming increasingly hollow as both Athens and Sparta sought to maintain their influence through other means.
Thucydides’ Historical Account
The great Athenian historian Thucydides provides our primary narrative of this turbulent period. His meticulous approach to recording events – dividing years into summer and winter campaigns – offers invaluable insight into the complex web of alliances and conflicts. Thucydides continued his account until Sparta and its allies ultimately defeated the Athenian empire, capturing the Long Walls and Piraeus after twenty-seven years of intermittent warfare.
What makes Thucydides’ account particularly valuable is his personal involvement in these events. Having served as an Athenian general before his exile, he gained unique access to information from both sides of the conflict. His banishment following the Amphipolis campaign ironically provided him with greater freedom to investigate events objectively, resulting in a remarkably balanced historical record despite his Athenian origins.
The Rise of Argive Power
As tensions between Athens and Sparta simmered, Argos emerged as a potential third power in Peloponnesian politics. The Corinthians, dissatisfied with Spartan leadership, secretly approached Argive officials with a bold proposal. They argued that Sparta sought to dominate the Peloponnese and suggested that Argos should take the lead in forming a defensive alliance of independent states that could resist Spartan hegemony.
The Argives, sensing an opportunity to expand their influence, acted swiftly. They passed a decree authorizing negotiations with any Greek state willing to join such an alliance, excluding only Athens and Sparta unless the Argive assembly approved their inclusion. Argos’ position had strengthened considerably during the Ten Years’ War, having remained neutral and profited from that neutrality while other states exhausted themselves in conflict.
Shifting Alliances in the Peloponnese
The first to join the new Argive alliance were the Mantineans and their allies, motivated by fear of Spartan retaliation for their expansion into Arcadian territory. Their defection from the Spartan alliance sent shockwaves through the Peloponnese, prompting other states to reconsider their allegiances. Many grew suspicious of a clause in the Athenian-Spartan treaty that allowed amendments by mutual consent, fearing this could lead to a joint Athenian-Spartan domination of Greece.
Sparta, recognizing the growing unrest, dispatched ambassadors to dissuade wavering states from joining the Argive alliance. They particularly chastised Corinth for instigating the movement and reminded them of their oath-bound obligations to the Peloponnesian League. The Corinthians responded with legalistic arguments, claiming their prior commitments to Thracian allies prevented them from fully accepting the Athenian-Spartan treaty.
The Complex Diplomatic Landscape
The diplomatic situation grew increasingly complex as Elis joined Corinth in alliance with Argos, motivated by a territorial dispute with Sparta over Lepreum. Meanwhile, Boeotia and Megara remained cautiously aligned with Sparta, their oligarchic governments distrustful of Argos’ democracy. This period saw constant negotiations, with alliances forming and dissolving as states sought to maximize their security and advantage.
Athens, for its part, consolidated its position by resettling Delians on their home island and dealing harshly with rebellious subjects like Scione. The Athenians grew increasingly frustrated with Sparta’s failure to compel its allies to comply with the peace terms, particularly regarding the return of Amphipolis. This mutual distrust would ultimately lead both powers to abandon their treaty obligations and return to open hostilities.
The Breakdown of Peace
The winter of 421/420 BCE proved decisive in the collapse of the peace. New Spartan ephors, some openly hostile to the treaty, assumed office. Secret negotiations between Spartan officials and Boeotian representatives revealed Sparta’s willingness to abandon its alliance with Athens if necessary. The Boeotians were encouraged to first ally with Argos, then bring Argos into alliance with Sparta – a complex realignment that would isolate Athens.
Meanwhile, Argos faced its own dilemma. Having expected Boeotian support that never materialized, and seeing Boeotia make separate terms with Sparta, the Argives feared isolation. Their attempts to form a broad anti-Spartan coalition faltered as key potential allies hesitated. Facing potential war against Sparta, Tegea, Boeotia, and Athens simultaneously, Argos made overtures to Sparta for a separate peace.
The Battle of Mantinea
These shifting alliances culminated in the pivotal Battle of Mantinea in 418 BCE, the largest land engagement of the Peloponnesian War period. Sparta, demonstrating remarkable military recovery from earlier setbacks, decisively defeated the allied forces of Argos, Mantinea, and Athens. This victory restored Sparta’s reputation as the preeminent land power in Greece and temporarily checked the growth of Argive influence.
The battle showcased Spartan military discipline at its finest. Despite initial tactical errors and being outmaneuvered, the Spartan army under King Agis II demonstrated superior training and cohesion, ultimately routing the allied forces. The psychological impact of this victory cannot be overstated – it reaffirmed Spartan dominance in the Peloponnese after years of uncertainty following the disaster at Sphacteria.
The Aftermath and New Alliances
In the battle’s wake, Sparta moved quickly to consolidate its position. Argos, its democratic faction weakened by the defeat, negotiated a separate peace with Sparta that effectively dissolved its recent alliances. The terms required Argos to abandon its claims on Epidaurus, release hostages, and accept Spartan oversight in Peloponnesian affairs. This agreement marked a significant reversal for Argive ambitions and restored Spartan hegemony in the region.
The political fallout continued as Sparta intervened to install oligarchic governments in Sicyon and Argos, further solidifying its control. However, these changes proved unstable – the Argive democracy soon reasserted itself, leading to internal conflict and eventually renewed fortification efforts with covert Athenian support. The cycle of alliance and betrayal continued, demonstrating the fundamental instability of the post-war settlement.
Enduring Rivalries and Future Conflicts
As the winter of 417/416 BCE closed, the broader conflict showed no signs of permanent resolution. Athens maintained its naval supremacy while Sparta reestablished its land dominance, creating a strategic stalemate. The failed peace had demonstrated that neither power could tolerate the other’s continued influence, setting the stage for the final, decisive phase of the Peloponnesian War.
The complex diplomatic maneuvers and shifting alliances of this period reveal the fundamental tensions in the Greek city-state system. Without mechanisms for genuine collective security or conflict resolution beyond temporary treaties, the cycle of war and fragile peace would continue until the eventual triumph of Sparta and the brief establishment of its hegemony – a victory that would prove as unstable as the peace it followed.