Prologue
Greece
The origins of such a conflict are complex. The primary causes were that Sparta feared the growing power and influence of the Athenian Empire. The Peloponnesian war began after the Persian Wars ended in 449 BCE. The two powers struggled to agree on their respective spheres of influence, absent Persia's influence. This disagreement led to friction and eventually outright war. Additionally, Athens and its ambitions caused increasing instability in Greece.
The profoundly different Athens and Sparta societies were also a significant factor in the war’s outbreak, which also had an ideological aspect. Over time the Athenians, who were the largest maritime power in the Aegean, dominated the Delian League. This era constituted the Golden Age of Athens and was concurrent with Plato, Socrates, and Aristotle's lives.
Gradually, the Athenians began to turn the Delian League into an Empire. Athens used its superior navy to intimidate its allies, and they eventually became mere tributaries of the Athenians. Sparta soon became very suspicious of Athens's growing power. Sparta was the head of the powerful Peloponnesian League, comprised of several large city-states, including Corinth and Thebes. The League was very concerned about the Athenian fleet because it allowed Athens to dominate Greece's seas.