The Peloponnesian War took place between the years 431-404 BCE and was a watershed event in the history of ancient Greece. It was, at its core, a conflict for the hegemony, or leadership, of the Greek world between Athens and the Delian League on one hand, and Sparta and the Peloponnesian League on the other. The main source used in this guide for the events of the war is Thucydides’s History of the Peloponnesian War, from which “The Melian Dialogue” is taken.

The end of the Persian Wars (499-449 BCE), in which Athens was a major player in the defeat of the Persian empire, saw a steady and exponential growth in the power of the Athenian city-state. Having organized the Delian League (so named because its treasury was located on the island of Delos) for mutual defense against the Persians, Athens used the funds to greatly expand its navy and force more of the Greek lands formerly under Persian control into the Delian alliance. As the leader, or hegemon, of the alliance, Athens increasingly used common resources to enrich itself, leading to growing resentment from its former allies. By the time the Peloponnesian War began, the Delian League had transformed into an Athenian empire.