Peloponnesian War, a war of thirty years' duration (431-404 B.C.) between Athens and Sparta, which ended in the supremacy of the latter, till the latter was overthrown at Leuctra by the Thebans under Epaminondas in 371 B.C. This war is the subject of the history of Thucydides.
Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)
Pelopidas * Peloponnesus