The Corinthian War, a Greek conflict lasting from 395 BCE until 387 BCE, pits Sparta against a coalition of four allied states; Thebes, Athens, Corinth, and Argos; which are initially backed by Persia.

The immediate cause of the war is a local conflict in northwest Greece in which both Thebes and Sparta intervene.

The deeper cause is hostility towards Sparta provoked by that city's "expansionism in Asia Minor, central and northern Greece and even the ... west".

The war is fought on two fronts, on land near Corinth and Thebes and at sea in the Aegean.

On land, the Spartans achieve several early successes in major battles, but are unable to capitalize on their advantage, and the fighting soon becomes stalemated.

At sea, the Spartan fleet is decisively defeated by a Persian fleet early in the war, an event that effectively ends Sparta's attempts to become a naval power.

Taking advantage of this fact, Athens launches several naval campaigns in the later years of the war, recapturing a number of islands that had been part of the original Athenian Empire during the 5th century BCE.Alarmed by these Athenian successes, the Persians stop backing the allies and begin supporting Sparta.

This defection forces the allies to seek peace.

The Peace of Antalcidas, commonly known as the King's Peace, is signed in 387 BCE, ending the war.

This treaty declares that Persia will control all of Ionia, and that all other Greek cities will be independent.

Sparta is to be the guardian of the peace, with the power to enforce its clauses.

The effects of the war, therefore, are to establish Persia's ability to interfere successfully in Greek politics and to affirm Sparta's hegemonic position in the Greek political system.