Causes of The Peloponnesian War

The causes of the Great Peloponnesian War cannot be directly accredited to the Spartans or the Athenians. The long-term rivalry between the expanding Athenian empire and the Peloponnesian league was supplemented the short-term crisis events such as the Corcyran criss, the Potidean dispute and the Megarian decree to push both sides into war making it difficult to blame one side for causing the war, although it is known that there were arguments within Sparta for and against starting a war, and conversely the Athenians looked like they were preparing for war. The issue is further complicated with the role Sparta’s ally, Corinth, played in causing the war, hence the various contributing factors of all parties made war inevitable.

The long term rivalry between Athens and Sparta has been perceived by the only primary historian recording the Peloponnesian war, Thucydides, as being the main cause of the war: “What made war inevitable was the growth of Athenian power and the fear which this caused in Sparta”[1](Thuc 1.23). The rivalry between Athens and Sparta had been growing since the victory over the Persians in which the two cities were united. In 479 BC Athens was hastily rebuilding her city walls and navy after the battle with the Persians to the alarm of Sparta[2](Thuc 1.91). By 460 BC, the once Delian League[3] turned Athenian Empire had started to show signs of betrayal to Sparta, in particular the friendship Athens acquired with Argos, one of Sparta’s enemies who remained neutral during the war with the Persians. Athens also started to frustrate Sparta’s main ally, Corinth leading to small-scale conflicts. Athens suffered some setbacks from the conflicts which in turn ended Athens’ short lived land empire. This led to the creation of the Thirty Years Peace of 445 BC, which created a temporary balance between Athens and Sparta.[4] (Thuc 1.115) This treaty only lasted for 15 years in a period called ‘the drift to war’ (445-431BC). This meant that any minor conflict could escalate into hostility between the two forces.[5] After the peace broke, the tensions between Athens and Sparta were growing, and some modern historians believe that in 433BC Sparta could have seen Athens’ attempt to develop trade links with poleis in Sicily and Southern Italy as continued growth of power and a threat to Peloponnesian power.[6] (Thuc. IV.102) Furthermore, the Athenian growth of naval superiority, and the huge financial resources gathered by Athens, was perceived by Sparta as Athens preparing for war. Due to Athenian consolidation of power in the ‘drift to war’ period, and how the Spartans perceived the Athenian growth, the long term tensions between Sparta and Athens became a considerable cause of the Peloponnesian war.