The First Peloponnesian War (460–445 BCE) was fought between Sparta as the leaders of the Peloponnesian League and Sparta's other allies, most notably Thebes, and the Delian League led by Athens with support from Argos. This war consisted of a series of conflicts and minor wars, such as the Second Sacred War. There were several causes for the war including the building of the Athenian long walls, Megara's defection and the envy and concern felt by Sparta at the growth of the Athenian Empire.

The First Peloponnesian War began in 460 BCE with the Battle of Oenoe, where Spartan forces were defeated by those of Athenian-Argive alliance. At first the Athenians had the better of the fighting, winning the naval engagements using their superior fleet. They also had the better of the fighting on land, until 457 BCE when the Spartans and their allies defeated the Athenian army at Tanagra. The Athenians, however, counterattacked and scored a crushing victory over the Boeotians at the Battle of Oenophyta and followed this victory up by conquering all of Boeotia except for Thebes.

Athens further consolidated their position by making Aegina a member of the Delian League and by ravaging the Peloponnese. The Athenians were defeated in 454 BCE by the Persians in Egypt which caused them to enter into a five years' truce with Sparta. However, the war flared up again in 448 BCE with the start of the Second Sacred War. In 446 BCE, Boeotia revolted and defeated the Athenians at Coronea and regained their independence.