The peloponnesian war was an ancient greek war fought in 431-404 B.C. by Athens and the Peloponnesian League which was led by Sparta. This war was divided into three stages, the first was the Archidamian war and in this first stage Sparta invaded many times Attica, while Athens took advantage of its strong navy to raid the coast of the Peloponnese trying to show that its empire was not resting. This period of war was ended in 421 B.C. when they signed the Peace of Nicias.That treaty however was left behind when new fighting arose.

In 415 B.C. Athens attacked Syracuse in Sicily with an army called the ''massive expeditionary force'', however the attacked failed and caused the death of the whole army. This hapenned in the final stage of the war, generally called the Decelean War, or the Ionian war. In this phase Sparta was receiving support from Persia.Persia supported Spartan rebellions in Athens, the following year Athens surrended.

The major cause of this war was the growth of Athenian Power, because it caused fear in Sparta. Athen's power came from Periclean imperialism and economic dynamism. Sparta wanted to restore its power, as a result Spartans felt hate towards Athens.The Peloponnesian War reshaped the Ancient Greek world. Athens, the strongest city state in Greece, was reduced while Sparta became the leading war of Greece.

It is believed that Sparta had an army of 30,000 hoplites with 2,000 cavalry and Athens had 13,000 hoplites and 1,200 cavalry. Sparta used the Corinthian vessels as a navy but it was no challenge for the strong athenian navy. Anyways Sparta had interests no where but the Peloponnesus where they had their influence. It is hard to believe that Spartans feared Athenians even when they had larger armies.

For a short period of time, Athens was ruled by the ''Thirty Tyrants''and democracy was suspended, this regime was set by Sparta after the war, later they were overthrown and democracy was established once again.