Causes of the Peloponnesian War

According to Thucydides, the cause of the Peloponnesian war was the “fear of the growth of the power of Athens” throughout the middle of the 5th century BC. The Peloponnesian war was long awaited by Thucydides; in fact there were many

reasons and events leading up to the start of military aggression. Resentment and tension between Sparta and Athens began after the Spartans chose not to continue in siege against the Persians but to return home.

Nonetheless, the Athenians continued to fight and began to show that they had a strong military and could stand without the Spartans. Because of this many of the smaller city-states on the islands in the Aegean Sea and in northern Greece became Athens’ allies; thus, they became known as the Delian league. The Athenians were collecting taxes from the other city-states in the Delian league therefore their fleet had become by far the largest and most fearsome navy in the region in conjunction with their infantry advancement. This tax was in exchange for the protection that the Athenian fleet and army provided. One of the Athenian leaders, Pericles, used some of the tax money to rebuild the Athens walls, for defensive purposes, and to offensive military growth. This show of Athenian power frightened the Spartans, and Corinthians as well, who now saw the Athenian growth of power as a threat.

Causing tension with the Spartans and Corinthians the Athenian navy came to the aid of the Corcyraeans against the Corinthians. The threatening Athenian strength became more apparent to the Spartans. This happened because Epidamnus became involved in a political struggle where the Democratic Party had taken control of the colony’s government and forced the aristocrats out of power. The aristocrats joined with a cruel, ruthless group and attacked the city and its surrounding areas seeking revenge from the democrats for their actions. Epidamnus began looking for help and sent a request to Corcyra for military involvement. Corcyra refused to help the Epidamnians in their political struggle and consequently they sought for the assistant of Corinth. Nonetheless, the Corinthians sent ships to stop the violence. The Corcyraeans saw the Corinthians interference as disrespectful so they decided to send their own ships to stop the Corinthians. Adding more fuel to the fire, the Corcyraeans made an alliance with Athens who already has their own feud with Corinth for many years. The Corinthian fleet engaged the Corcyraeans and consequently the Corinthians lost the battle. This defeat fueled the Corinthians passion against the Athenians even more.

The final event that caused tension leading up to the outbreak of violence in the Peloponnesian War was when Potidaea, a member of the Delian league, rebelled against Athenian control. The city-state built barricades to resist Athenian army occupation which incited rebellion all over in the region in Chalcidice and Bottiaea. The Athenians sent troops into the region by ship, but they were also fighting the Macedonians in the same region and had difficult time suppressing that revolt. When Athens ultimately made a treaty with Perdiccas, the Macedonian leader, they were then turned-on by the Macedonians as they began fighting side-by-side with the Corinthians, who had come to the defense of the Potidaeans. Despite their recent setbacks, the Athenians were able to gain control of most of the region upon the arrival of reinforcements.

Corinth called a meeting of the Peloponnesian assembly at Sparta because they saw that their own citizens were now trapped in Potidaea. Almost immediately following this meeting the Peloponnesian decision was to declare war because the complaints against the Athenian Empire were deemed irreconcilable. The Spartan and Peloponnesian demanded that the Athenians withdraw from Potidaea and that all the city-states in northern Greece be given their freedom.

Despite the declaration of war, three ambassadors were sent to Athens over the course of winter in attempts to declare peace; however, neither side could come to a resolution. Nonetheless in the summer of 431 BC the Thebans, a member of the Peloponnesian League, attacked Plataea, Athens oldest ally. This drew Athens to Plataea’s defense, which in turn brought the Spartans and Corinthians to the side of their ally which marked the beginning of the Peloponnesian War.