->''"Creator/{{Thucydides}}, an Athenian, wrote this history of the war between the Peloponnesians and the Athenians, from the moment the conflict broke out, for he believed that it would be a great war and more worthy of remembrance than any that had preceded it. This belief was not without its grounds."''

The Peloponnesian War, one the largest conflicts in the Greek City State era, pitted the Athenian-led Delian League (sometimes also known as the Athenian Empire) against the Spartan-led Peloponnesian League. The war can be separated into three phases:

'''Phase One''', the "Archidamian War," established the Athenian Navy as a preeminent dominant force in the sea, having able to suppress dissent in its empire as well as foil Spartan invasions in the Athenian home state of Attica. This phase lasted from 431-421 BCE.

'''Phase Two''' saw an attempted Athenian invasion of Sicily in 415 BCE, in what can only be described as an act of wanton imperialism. The war pitted Athens against the city-state of Syracuse, which was nominally supported by Sparta. In a shocking turn, the entire invading Athenian army was massacred in 413 BCE, changing the tide of the war. This section of the Peloponnesian war is widely remembered to this day as an example of the disastrous results that can happen if a war is undertaken poorly or without proper justification.

'''Phase Three''', the "Ionian War," was the final phase of the conflict. The Spartans sieged Athens by land, and the Athenian Navy was unable to break the siege, though it could supply itself with grain due to the lack of a significant Spartan naval presence. With support from the Persians, Sparta began to develop a powerful navy, and it began to fight the Athenian navy across the Aegean Sea. With the Battle of Aegospotami (near modern-day Turkey) the Spartan Navy won a decisive victory over that of Athens. This defeat marked the end of the Athenian Empire, which surrendered in 404 BCE.

!!The Peloponnesian War is often associated with the following tropes:

* AllForNothing: The Spartans had three concrete war aims at the outset: The demolishing of the Long Walls, destruction of the Athenian fleet, and displacement of the Athens’s democratic government. In 404 BCE, all three were accomplished. And within a generation a democratic Athens, protected by Long Walls, was once more the premiere naval power in the Aegean. Well played, Sparta.
* {{Anticlimax}}: The Athenian fleet was destroyed when the Spartans caught it on shore with all the crews looking for food and wiped it out without a battle.
** Something similar had happened in one of the four battles of Syracuse harbour.
* BadassArmy: The Spartans and Thebans on land. (Though the Spartans are something of a subversion of the trope in this context: As Aristotle quipped, what was amazing of the Spartans was not the quality of their drill, but that they drilled at all). The Athenian imperial navy played this trope razor-straight, succeeding in destroying no less than three entire Spartan fleets during the Ionian War and only meeting defeat when it was caught on land at Aegospotami.
* BalanceOfPower: Sparta was afraid that Athens was unbalancing this.
* TheCassandra: For all of his political betrayals, Alcibiades wasn't one to give bad or dishonest military advice. In 405 BCE, the Athenians were moored at Aegospotami on a beach that left them exposed to attack. When Alcibiades, who happened to be living near by, advised the Athenians of their position and offered help. He was told to get stuffed, and Athens lost the battle which led to their surrender in 404.
* ChronicBackstabbingDisorder: Alcibiades started with Athens, went to Sparta, went back to Athens, went back to Sparta. Xenophon didn't speak well of him.
* CrowningMomentOfAwesome: For many, Pericles' eulogy of the dead of the first year of the war, as recorded (or rewritten) by Thucydides, which also sets out why Athens and its democracy was so great. What the (much shorter) Gettysburg Address was to UsefulNotes/TheAmericanCivilWar, this was to the Peloponnesian War.
** While a great speech, this is a pretty rubbish Crowning Moment of Awesome given the magnitude of the war. Possibly the greatest one was Alcibiades' return to the Athenian Army, stationed at Samos, in the latter stages of the war. Athens was losing, badly, and could barely hold on to what little territory they had left. Alcibiades rejoined the army from exile, gave a bad-ass, balls-out speech about how they need to man-the-hell-up, then led them in a campaign of reconquest, destroying the Spartan fleet, defeating multiple Persian armies, reconquering all the cities from the Hellespont to the Bosporous and returning home to Athens in glory, with the Athenian ships glittering from captured shields hung about their prows and with dozens of enemy vessels in tow. The Athenians rushed out to the shore to meet him as they returned, and crowned him with garlands, made him general at land and sea and virtual dictator of the city and its empire, and Athens was firmly back in the war. That, my friends, is a Crowning Moment of Awesome.[[note]]Which he then went on to mess up, with the Athenian defeat at the Battle of Notium, which happened because Alcibiades left the wrong guy in charge.[[/note]]
* DarkHorseVictory: Thanks to Sparta and Athens beating the snot out of each other, then Sparta and Thebes beating the snot out of each other, a certain Philip of Macedon (who had a [[UsefulNotes/AlexanderTheGreat rather famous son]]) was able to come in and get warmed up.
* EasilyForgiven: Alcibiades, who betrayed everyone. [[WhyDontYouJustShootHim Why in the world did no one give him some hemlock]]?
** The man was a [[FourStarBadass scary competent strateg]][[GratuitousForeignLanguage os]]. The Athenian navy was MadeOfWin with him in command. This made Athens a bit {{Tsundere}} for him, and vice versa.
* ForeverWar: I doubt anyone remembered how it began by the end.
** Except obviously for Thucydides. He was a former Athenian commander who was sent into exile after a defeat and wrote a history of the war that is generally considered to be the first work of "proper", i. e. critical history. He started it with a summing up of what the two sides said were the reasons for the war and what he thought were the real reasons, and for good measure chronicled the 50 years leading up to it.
* FourStarBadass: Kleon of Athens, who was largely responsible for forcing Sparta to terms at the end of the Archidamian war. For the Spartans Brasidas and Lysander were the great heroes of the war.
* GambitPileup
* GameChanger: The failed invasion of Sicily by Athens and the destruction of their army was this; this crippling defeat would be a major factor leading to their loss of the entire war.
* GreyAndGrayMorality: A classic example.
* HeyItsThatGuy: Creator/{{Socrates}} ThePhilosopher was a hero at the Battle of Delium.
* HoistByHisOwnPetard: The invasion of Syracuse by Athens.
* KingmakerScenario: Persia played the kingmaker part in the last phase of the war.
* LawfulStupid: Nicias. While the Athenians were cutting their losses and preparing to leave Syracuse, there was a lunar eclipse. According to the auspices taken afterward, Nicias had the army wait on [[LawfulStupid Syracuse's doorstep for 28 days]]. [[FromBadToWorse Guess what happened]].
** To be fair there was no way people at the time could be sure that they wouldn't [[TemptingFate offend "someone important".]]
* MagnificentBastard: Alcibiades and Lysander.
* NotSoDifferent: Athens and Sparta ended up being guilty of things they accused each other of.
** Sparta's stated objectives were to ensure that each polis (city-state) would be independent and free of slavery, yet they hated anyone who seemed to have so much as a ''hint'' of sympathy for helots. Sparta also prided itself on being pure, free of corruption, and having nothing to do with the Persians, yet in the end they had to pay the Persians to help them against Athens.
** Athens was a democracy, but also openly imperial.
* OneSceneWonder: Diodotus, an otherwise unknown Athenian who almost single-handedly prevented the Athenians from brutally punishing the people of Mytilene for revolting against Athenian rule. After a mission had been dispatched to Mytilene with instructions to kill all the men and enslave all the women and children, the Athenians began to have second thoughts. The ensuing debate saw Cleon call the Athenians out for being cowards, but Diodotus -- in his only appearance ever in history -- persuaded the Athenians that the rest of the world would perceive it as DisproportionateRetribution, and a second mission went out after the first one to countermand the order. It got there [[JustInTime just as the commander of the first mission was reading the sentence to the Mytilenians, but before it had been carried out]].
* PyrrhicVictory: The war weakend the victor Sparta as much as the defeated Athens. The true victors wer resurgent Persia and rising Thebes and Macedonia.
* RammingAlwaysWorks: [[TruthInTelevision Truth in Television]] at its finest! …or is it? The scholarly community does not question that trireme warfare was a close-quarters affair, but the exact tactics utilized by the Athenians remain a debated. Tended to be played straight by Spartans during the Ionian War.
* RegimeChange: In the end, Sparta stuck the Thirty Tyrants in Athens and called it a day.
* TheSiege: From Athens' point of view much of the war was this as the Spartans were always held back by the city's wall and the "Long Walls" that connected it to its harbour Piraeus. However, the cramped conditions inside the walls facilitated [[ThePlague the plague]] that decimated the Athenian population, killing Pericles among others.
* TheSpartanWay: Well, ''duh''.
* StrangerInAFamiliarLand: Specifically many Spartans like Lysander.
* WarIsHell: It was at this time that the first antiwar plays were made; ''Theatre/{{Lysistrata}}'' is the one that has stood the test of time.
** Some parts of Thucydides' "Peloponnesian War" also stick in the mind, e. g. the war of Athens against Melos (featuring the famous "Melian dialogue") which ended with the Athenians killing all adult male Melians and selling the women and children into slavery.
* WeHaveReserves: The Spartan naval campaign during the Ionian War ran on this trope, as the Spartans built and crewed a navy from scratch using Persian gold following the Sicilian Expedition, and proceeding to do it ''four'' more times after being defeated at Abydos, Cynossema, Cyzicus, and Arginusae.

!!Depictions in fiction:

* ''Theatre/{{Lysistrata}}''
* ''Theatre/TheAcharnians''
* Thucydides' ''History of the Peloponnesian War'' is one of the first modern analyses of a war. He died sometime before the end of the war, so it doesn't cover the last few years, but nevertheless, it's usually accepted as a nice (generally) unbiased version.