The Peloponnesian War erupted from deep-rooted tensions between Athens and Sparta. Their contrasting political systems, Athens' growing power, and economic rivalries fueled the conflict. Failed diplomacy and shifting alliances set the stage for war.

Key events like the Megarian Decree and Potidaean Revolt pushed tensions to the brink. Pericles' leadership in Athens, emphasizing naval power and refusing compromise, further escalated the situation. These factors combined to make war inevitable.

Tensions between Athens and Sparta

Political and Ideological Differences

• Athens and Sparta had fundamentally different political systems leading to ideological tensions between the two city-states
  • Athens was a democracy where citizens participated in decision-making (Athenian Assembly)
  • Sparta was an oligarchy ruled by a small group of elite citizens (Spartan Gerousia)
• The contrasting political ideologies of Athens and Sparta created a deep-rooted rivalry and mistrust between the two city-states
  • Athenian democracy was seen as a threat to the traditional aristocratic order championed by Sparta
  • Sparta viewed Athens' democratic system as potentially destabilizing to the Greek world

Economic and Military Power Imbalance

• Athens' growing economic and military power, particularly its naval dominance, threatened Sparta's traditional land-based hegemony in the Greek world
  • Athens had a strong navy and a thriving maritime trade network (Piraeus port)
  • Sparta's strength lay in its formidable land army and its control over the Peloponnesian League
• The formation of the Delian League, led by Athens, and its transformation into an Athenian empire, further exacerbated the power imbalance and heightened Spartan concerns
  • The Delian League was initially formed to counter the Persian threat (Ionian Revolt)
  • Athens gradually turned the league into an empire, using its power to dominate and control other city-states
• Economic competition between Athens and Sparta, particularly in terms of trade and access to resources, contributed to the escalating tensions
  • Athens' control over key trade routes and its ability to impose economic sanctions (Megarian Decree) threatened Sparta's interests
  • Sparta and its allies, such as Corinth, feared the growing economic influence of Athens in the Greek world

Failure of Diplomacy

• The Thirty Years' Peace, signed after the First Peloponnesian War, failed to address the underlying causes of conflict and merely served as a temporary truce
  • The peace treaty did not resolve the fundamental differences between Athens and Sparta
  • The treaty's terms, such as the prohibition on forming new alliances, were often violated or circumvented by both sides
• The breakdown of diplomatic relations between Athens and Sparta, as evidenced by the dismissal of Spartan envoys and the refusal to negotiate, signaled the inevitability of war
  • Athens refused to accept Spartan demands, such as the repeal of the Megarian Decree
  • Spartan envoys were dismissed from Athens without a satisfactory resolution to the growing tensions

Alliances and Diplomacy in the Peloponnesian War

Peloponnesian League and Athenian Alliances

• The Peloponnesian League, led by Sparta, served as a counterweight to Athenian power and included many city-states that were wary of Athenian dominance
  • The league included powerful city-states such as Corinth, Thebes, and Megara
  • The Peloponnesian League provided a platform for Sparta to rally support against Athens
• Athens relied on its own network of alliances, primarily through the Delian League, to maintain its influence and power
  • The Delian League included many city-states in the Aegean Sea and Asia Minor (Chios, Samos)
  • Athens used its position as the leader of the Delian League to extract tribute and enforce its policies

Shifting Allegiances and Diplomatic Maneuvering

• The shifting allegiances of smaller city-states, such as Megara and Potidaea, played a crucial role in the diplomatic maneuvering leading up to the war
  • Megara, initially an ally of Athens, defected to the Peloponnesian League due to economic grievances (Megarian Decree)
  • Potidaea, an Athenian colony, revolted against Athenian rule with the backing of Corinth and Sparta
• Sparta's decision to intervene on behalf of its allies, particularly Corinth, in disputes with Athens, heightened the risk of open conflict
  • Corinth, a powerful member of the Peloponnesian League, pressured Sparta to take action against Athens
  • Sparta's ultimatum to Athens, demanding the repeal of the Megarian Decree and the restoration of autonomy to Potidaea, represented a final attempt to avoid war through diplomacy

Key Events Leading to the War

Megarian Decree and Economic Sanctions

• The Megarian Decree, imposed by Athens, banned Megarian merchants from Athenian markets and ports, severely damaging Megara's economy and prompting them to seek Spartan support
  • The decree was a punitive measure taken by Athens in response to Megara's alleged support for Corinth
  • The economic sanctions imposed by the decree had a devastating impact on Megara's trade and economy
• The Megarian Decree demonstrated Athens' willingness to use its economic power to punish and coerce other city-states
  • The decree was seen as an act of aggression by Sparta and its allies
  • The economic sanctions imposed by Athens further strained the already tense relations between the two city-states

Potidaean Revolt and Spartan Intervention

• The Potidaean Revolt, in which the Athenian colony of Potidaea rebelled against Athenian rule with the backing of Corinth and Sparta, served as a catalyst for the war
  • Potidaea was a strategically important city on the Chalcidice peninsula
  • The revolt challenged Athens' authority and control over its colonies and allies
• Sparta's support for the Potidaean Revolt and its ultimatum to Athens marked a significant escalation in the conflict
  • Sparta demanded that Athens restore autonomy to Potidaea and repeal the Megarian Decree
  • Athens' refusal to comply with Sparta's demands made war virtually inevitable

Athenian Confidence and Spartan Alarm

• These events demonstrated the willingness of Athens to use its economic and military power to enforce its will on other city-states, alarming Sparta and its allies
  • Athens' actions, such as the Megarian Decree and its handling of the Potidaean Revolt, were seen as aggressive and expansionist
  • Sparta and its allies feared that Athens' growing power and influence would threaten their own autonomy and security
• The Spartan ultimatum to Athens, demanding the repeal of the Megarian Decree and the restoration of autonomy to Potidaea, represented a final attempt to avoid war through diplomacy
  • Sparta's ultimatum was a clear indication of its willingness to go to war if its demands were not met
  • Athens' rejection of the ultimatum and its confidence in its own strength made the outbreak of the Peloponnesian War inevitable

Pericles' Influence on Athenian Policy

Pericles' Leadership and Strategic Vision

• Pericles, as the leading statesman of Athens, played a pivotal role in shaping Athenian foreign policy and military strategy
  • Pericles was elected strategos (general) multiple times and had significant influence over Athenian decision-making
  • Pericles' vision for Athens emphasized the city's naval power, cultural superiority, and democratic ideals
• Pericles' policy of consolidating Athenian power and refusing to compromise with Sparta and its allies, even in the face of war, reflected his confidence in Athens' strength and his belief in the superiority of Athenian democracy
  • Pericles believed that Athens' naval supremacy and economic strength would allow it to outlast Sparta in a prolonged conflict
  • Pericles' unwavering commitment to Athenian democracy and his refusal to appease Sparta's demands contributed to the escalation of tensions

Military Strategy and Defensive Measures

• Pericles' strategy of relying on Athens' naval supremacy and avoiding direct land engagements with Sparta's superior hoplite army, set the stage for a prolonged conflict
  • Pericles recognized that Athens could not match Sparta's land-based military strength
  • By focusing on naval warfare and maintaining control over the Aegean Sea, Pericles hoped to wear down Sparta and its allies over time
• Pericles' decision to bring the population of Attica within the walls of Athens to protect them from Spartan invasions, while effective in the short term, had significant long-term consequences for the city's health and morale
  • The overcrowding and unsanitary conditions within the city walls led to the outbreak of a devastating plague (Plague of Athens)
  • The plague claimed the lives of many Athenians, including Pericles himself, and had a demoralizing effect on the city's population

Periclean Building Program and Its Consequences

• The Periclean building program, which included the construction of the Parthenon and other monumental structures, served to assert Athenian wealth and power, but also drained financial resources that could have been used for the war effort
  • The construction of the Parthenon and other temples on the Acropolis was a symbol of Athens' cultural and artistic achievements
  • The building program was financed through the tribute collected from the Delian League, which strained Athens' relations with its allies
• The diversion of resources towards the building program and the maintenance of Athens' cultural prestige may have come at the expense of military preparedness and strategic flexibility
  • The cost of the building program and the subsequent plague outbreak weakened Athens' financial position and its ability to sustain a prolonged war effort
  • Pericles' death in 429 BCE left a leadership vacuum in Athens and contributed to the city's eventual defeat in the Peloponnesian War