The Peloponnesian War ( 431 - 404 B.C )The War fought between the two leading city-states in ancient Greece, Athens and Sparta.
The Peloponnesian War (431-404 B.C.) took place between the Athenian empire and Peloponnesian league lead by the Spartans. The Peloponnesian league was a coalition of the Thebes, Corinth and Sparta.
The war was divided into 3 phases: The Archidamian War, The Sicilian war and The Ionian or Decelean War: phase. The war commenced on 4 April 431 B.C. when the Thebans launched a surprise attack on Plataea, who as a partner of Athens. The war ended on 25 April 404 B.C. when Athens surrendered.
The Peloponnesian War remodeled the entire Greek state. The Athenian empire, which was a stronger side prior to the war, was reduced to a mere vulnerable slave of Sparta. After the war, Sparta was the ruling state of Greece. The war destroyed the economies and brought poverty and sufferings to the state. Athens could never gain its lost prosperity that it was proud of, pre-war.
The main reason for the launch of the war was the Spartan fear of Athens's growing power and prosperity. Athens rule over most of the Mediterranean region along with Greece/Hellas, 50 years preceding the war, instigated the war.
According to Thucydides, that after Athens became the leader of the Delian League, they became the supreme power known as the Athenian Empire. They nearly drove out the Persians from their regions of Aegean and occupied supremacy over a large number of territories. Athens naval power was also growing day-by-day endangering the bordering states.
During the Persian war in 480 BC, Athens power had grown by leaps and bounds and with the help of its allies continued its attacks on the Persian territories of Ionia and Aegean. Athens also constructed walls around its empire to save them from Spartan land attack, when the Persians fled Greece. This enraged the Spartans, who took no action at that time.
In 459 BC Athens took advantage between the Megara and Corinth war siding with Megara. This helped them gain a foothold on the Isthmus of Corinth. This resulted in a war, known as the 'The First Peloponnesian War' fought between Athens and Sparta, Corinth, Aegean and other states. At the end of the war, however, Athens backed out from Greek mainland, due to an enormous attack by the Spartans. A thirty years treaty was signed between Athens and Sparta in 446 BC.
The Thirty Years peace treaty weathered its first experience when Samos, an Athens ally, rebelled. At that time a Spartan interference, could have resulted into a huge war, but the Spartans along with its allies decided not to intervene. The revolt was crushed.
The second reason of the war was, after Athens made an alliance with Corcyra, Rhegium and Leontini, the naval power in un-destroyable. Corcyra was Corinth's enemy. This endangered food supply to the region to the Peloponnese city. Regarding this point, the Peloponnesian War was a trade war. The Corinth, encouraged the Spartans to take up arms, backed by Megara and Aegean who had unwillingly became an Athenian ally.
Further instigation was strict sanctions Megara, in spite of being an Athens ally. These sanctions forbade Megara of having any economic transactions with Athens. Known as the Megarian decree this was the last straw, and became a major contributing factor in the war.