The triumph of the great Athenian fleet and its rout of Xerxes' Persian forces at the sea battle of Salamis in 480 BC launched Athens upon its "golden age" of prosperity, power and cultural achievement. At the same time, however, it planted the seeds that would lead to Athens' subsequent overreaching and defeat.

Internally, political control of Athens after the victory over Persia passed from an aristocracy to the common people. Externally, Athens became an imperial force. The magnificent fleet that had served her so well at Salamis projected her trade throughout the Mediterranean. Yet Athens' success brought a certain arrogance that led her to ignore needs and concerns of her neighbors, many of whom had been valuable allies in the Persian conflict. Relations with Corinth and Aegina led to a brief war in 459 BC in which Athens easily prevailed.

When relations between Corinth and Athens next reached a crisis in 431 BC, Corinth deftly aligned Sparta and its Boethian allies as its protectors, playing on their fears of ever-increasing Athenian power. The military strength of Sparta on land was an effective counterpoint to Athens' naval power. Twenty-seven years of seesaw warfare ensued. The Peloponnesian War, despite its name, was not limited to the Greek states of the mainland. The Athenian attack on Syracuse in Sicily was one of the major engagements of the conflict and a significant factor in Athens' final surrender.