As the name implies, this was not a smooth war. How can an elephant really ever fight a whale? And even if they did battle, it's doubtful one would truly prevail over the other, as both are kings only in their elements. Thus, the nickname for one of history's most awful wars was aptly dubbed.
And the Age of Pericles ignited it all. Some of the most atrocious war crimes any Greek ever committed occurred during and after the Great Peloponnesian War. But who fought it? Not too long after the end of Persian king Xerxes I's invasion into Greece and his ultimate defeat by a united Greece at Plataea a year later, where even the reclusive Spartans made a legendary stand against the Persian invasion at the Battle of Thermopylae (the 300), the Athenians and other Greeks found themselves as true world superpowers. After the Persians failed, the Greek Golden Age ensued, where most Greeks were free to roam the Mediterranean completely unabashed of other cultures and invaders and pirates, for they all knew that the rest of the ancient world would not dare invade any Greek city for a long time after the humiliating defeat of the mighty Persian empire. It was with this peace that tensions grew not between the Greek and other cultures, but with fellow Greek city-states. Sparta, the legendary city-state with the ancient world's most legendary army, found itself in an undeclared power struggle with the Athenians who were clearly enjoying their new status of victors of the Battle of Salamis, the decisive battle that won the second invasion into Greece by the Persians by Xerxes I, which simultaneously took place just after the Spartan defeat at Thermopylae by the other half of Xerxes' invading forces. The Athenians then defeated the remaining Persian army at Plataea.
Virtually all of Greece united against Athens, but Athens held some Greek cities by force, virtually enslaving them to provide food, silver, and wood for their fleet. The Spartan strategy during the first war was known as the Archidamian War (431-421 BC) named after Sparta's king Archidamus II, was to invade the land surrounding Athens, siege the city of Athens and raze all crops, attempting to starve the city into surrender or death. This did not work since Athens was a naval power and freely left its ports to neighboring Greek cities and simply took their food and supplies by force. It was rare at this point that Pericles allowed for land battles to ensue, as Sparta was far superior on land.
Pericles like he was a demigod, and he advised the Athenians to avoid open battle with the far more numerous and better trained Spartan hoplites, relying instead on the fleet. The Athenian fleet, the most dominant in Greece, went on the offensive, winning a victory at Naupactus. In 430, however, an outbreak of a plague hit Athens due to the long siege from Sparta, where such close quarters with so many people spread the plague extremely fast, killing over 30,000 Athenian citizens, including Pericles since he often walked in the poor quater of Athens to rally support like a true man of the people. This cost him his life, as plagues always infect the poor before the rich. The plague was so horrific that even the Spartan siege and invasion was abandoned.
After Pericles died, the Athenians decided to bring the war to Sparta itself and its allies. Cleon and Demosthenes succeeded some in their naval raids on the Peloponnese, but truly struck the weak spot of Sparta when they caused the Helots, a slave population that Spartans were dependent on for overall survival, broke free in a small resistances after Athens struck Pylos on a tiny island called Sphacteria next to the Peloponnese, thus the course of the first war turned in Athens's favor when many of these Helots ran away, some even joining Athens at Pylos against Sparta itself. The Battle of Pylos ensued as a necessary response by Sparta in 425 BC, however Demosthenes trapped a group of Spartan soldiers on this island of Sphacteria as he waited for them to surrender. Weeks later, though, Demosthenes proved unable to finish off the Spartans. After boasting that he could put an end to the affair in the Assembly, the inexperienced Cleon won a great victory at the Battle of Sphacteria. The Athenians captured between 300 and 400 Spartan hoplites. The hostages gave the Athenians a bargaining chip. After these battles, the Spartan general Brasidas raised an army of allies and helots and conquered The Battle of Amphipolis in Thrace, which controlled several nearby silver mines; their product supplied much of the Athenian war fund. From Athens, Thucydides failed to stop the Spartan army in time and was exiled for his failure.
Battle of Notium led by general Lysander against Alcibiades of Athens . The Athenians came out victorious at the battle of Arginusae, where Callicratidas of Sparta had lost 70 ships while Athens lost only 25, but the weather denied the Athenians the final blow against the devastated Spartans and ultimately cost Athens the war after the city rose in outrage in an outrageous trial against the top naval commanders for their failures to crush Sparta when she was wounded. The trial resulted in the execution of six of Athens’s top naval commanders. Athens thereafter led a demoralized navy which may have cost them the war, for Lysander went to the Hellespont to destroy Athens' grain supplies, starving them do death if they did not surrender. Athen was indeed starving to death and was forced to attempt to fight Lysander at Threatened with starvation, the Athenian fleet had no choice but to fight in 405 BC at the battle of Aegospotami, destroying 168 ships and capturing some three or four thousand Athenian sailors. Only 12 Athenian ships escaped.
Athens and her allies surrendered in 404 BC, and her walls were torn down by the Spartans, and officially became a new Spartan city that year in the epic conclusion of the Great Peloponnesian War. Sadly, it did not end there, as the Spartans were far from saints, and the new city "ruled" by the militaristic Sparta simply caused bitterness among the Athenians, and the atrocities continued, for now Athens was basically enslaved. The Golden Age was definitely over, and the Greeks would never be quite the same after that.