The
Peloponnesian War (431–404 BC) was an
ancient Greek war fought by
Athens and its
empire against the
Peloponnesian League led by
Sparta. Historians have traditionally divided the war into three phases. In the first phase, the Archidamian War, Sparta launched repeated invasions of
Attica, while Athens took advantage of its naval supremacy to raid the coast of the
Peloponnese attempting to suppress signs of unrest in its empire. This period of the war was concluded in 421 BC, with the signing of the
Peace of Nicias. That treaty, however, was soon undermined by renewed fighting in the Peloponnese. In 415 BC, Athens dispatched a
massive expeditionary force to attack
Syracuse in
Sicily; the attack failed disastrously, with the destruction of the entire force, in 413 BC. This ushered in the final phase of the war, generally referred to either as the Decelean War, or the Ionian War. In this phase, Sparta, now receiving support from
Persia, supported rebellions in Athens' subject states in the
Aegean Sea and
Ionia, undermining Athens' empire, and, eventually, depriving the city of naval supremacy. The destruction of Athens' fleet at
Aegospotami effectively ended the war, and Athens surrendered in the following year.
Corinth and
Thebes demanded that Athens should be destroyed and all its citizens should be enslaved but Sparta refused.