First Peloponnesian War

The First Peloponnesian War, fought from 460 to 445 BC, pitted Sparta and the Peloponnesian League, with allies such as Thebes, against the Delian League led by Athens with support from Argos. It was a series of linked conflicts and minor wars, among them the Second Sacred War, and arose from the building of the Athenian long walls, the defection of Megara and Spartan fear at the growth of the Athenian Empire. It opened in 460 BC with the Battle of Oenoe. Athens won at sea and for a time on land, was beaten at Tanagra in 457 BC, then won a crushing victory at Oenophyta and conquered Boeotia except for Thebes. Athenian defeat in Egypt in 454 BC led to a five years truce, and the loss at Coronea in 446 BC ended Athenian control of Boeotia. The war closed with the Thirty Years Peace of the winter of 446 to 445 BC, under which both sides kept the core of their empires, Athens ruling the sea and Sparta the land. The fighting resumed in 431 BC as the Second Peloponnesian War.