Editing Peloponnesian War (section)

== Prelude ==
[[File:Fragment of the Athenian Tribute List, 425-424 BCE.jpg|thumb|Fragment of the Athenian Tribute List, 425–424 BC]]

[[Thucydides]] summarised the situation before the war as: "The growth of the power of Athens, and the alarm which this inspired in [[Sparta|Lacedaemon]], made war inevitable".<ref name=":3">{{Cite web |title=Thucydides, The Peloponnesian War, Book 1, chapter 1 |url=http://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.01.0200&redirect=true |access-date=26 December 2024 |website=www.perseus.tufts.edu}}</ref> The nearly 50 years before the War had been marked by the development of Athens as a major power in the Mediterranean world. Its empire began as a small group of city-states, called the [[Delian League]]&nbsp;– from the island of [[Delos]], on which they kept their treasury&nbsp;– that formed to ensure that the [[Greco-Persian Wars]] were over. After defeating the [[Second Persian invasion of Greece]] in the year 480 BC, Athens led the coalition of Greek city-states that continued the Greco-Persian Wars with attacks on Persian territories in the Aegean and Ionia. What ensued was a period which Thucydides called the [[Pentecontaetia]], in which Athens increasingly became an empire,<ref name=":2" /> carrying out an aggressive war against Persia and increasingly dominating other city-states. Athens brought under its control all of Greece except for Sparta and its allies, ushering in a period now called the [[Athenian Empire]]. By mid-century, the Persians had been driven out of the Aegean and had ceded control of vast territories to Athens. Athens had greatly increased its own power; a number of its formerly independent allies were reduced, over the course of the century, to the status of tribute-paying subject states of the Delian League. This tribute was used to fund a powerful fleet and, after the middle of the century, massive public works in Athens, causing resentment.<ref name=":1" />

Friction between Athens and the Peloponnesian states, including Sparta, began early in the Pentecontaetia. In the wake of the departure of the Persians from Greece, Sparta sent ambassadors to persuade Athens not to reconstruct their walls, but was rebuffed. Without the walls, Athens would have been defenseless against a land attack and subject to Spartan control.<ref name=":3" /> According to Thucydides, although the Spartans took no action then, they "secretly felt aggrieved".<ref name=":3" /> Conflict between the states flared up again in 465 BC, when a [[helot]] revolt broke out in Sparta. The Spartans summoned forces from all of their allies, including Athens, to help them suppress the revolt. Athens sent out a sizable contingent (4,000 [[hoplites]]), but upon its arrival, this force was dismissed by the Spartans, while those of all the other allies were permitted to remain. According to Thucydides, the Spartans did this out of fear that the Athenians would switch sides and support the helots; the offended Athenians repudiated their alliance with Sparta.<ref name=":3" /> When the rebellious helots were finally forced to surrender and permitted to evacuate the state, the Athenians settled them at the strategic city of [[Nafpaktos#Antiquity|Naupaktos]] on the [[Gulf of Corinth]].<ref name=":3" />

In 459 BC, there was a war between Spartan allies [[Megara]] and [[ancient Corinth|Corinth]], which were neighbors of Athens. Athens took advantage of the war to make an alliance with Megara, giving Athens a critical foothold on the [[Isthmus of Corinth]]. A 15-year conflict, commonly known as the [[First Peloponnesian War]], ensued, in which Athens fought intermittently against Sparta, Corinth, [[Aegina]], and a number of other states. For a time during this conflict, Athens controlled not only Megara but also [[Boeotia]]. But at its end, a massive Spartan invasion of Attica forced Athens to cede the lands it had won on the Greek mainland, and Athens and Sparta recognized each other's right to control their respective alliance systems.<ref name=":1" /> The war was officially ended by the [[Thirty Years' Peace]], signed in the winter of 446/5 BC.<ref>{{Cite book |last=Bagnall |first=Nigel |title=The Peloponnesian War: Athens, Sparta and the Struggle for Greece |date=2006 |publisher=Thomas Dunne Books |isbn=978-0-312-34215-9 |edition= |location=New York}}</ref>

=== Breakdown of peace ===
[[File:Map athenian empire 431 BC-en.svg|right|upright=1.3|thumb|The Delian League in 431 BC]]

The Thirty Years' Peace was first tested in 440 BC, when Athens's powerful ally [[Samos]] [[Samian War|rebelled from its alliance with Athens]]. The rebels quickly secured the support of a Persian [[satrap]], and Athens faced the prospect of revolts throughout its empire. The Spartans, whose intervention would have been the trigger for a massive war to determine the fate of the empire, called a congress of their allies to discuss the possibility of war with Athens. Sparta's powerful ally Corinth was notably opposed to intervention, and the congress voted against war with Athens. The Athenians crushed the revolt, and peace was maintained.<ref name=":1" />

The more immediate events that led to war involved Athens and Corinth. After a defeat by their colony of [[Korkyra (polis)|Corcyra]], a sea power that was not allied to either Sparta or Athens, Corinth began to build an allied naval force. Alarmed, Corcyra sought alliance with Athens. Athens discussed with both Corcyra and Corinth, and made a defensive alliance with Corcyra. At the [[Battle of Sybota]], a small contingent of Athenian ships played a critical role in preventing a Corinthian fleet from capturing Corcyra. In order to uphold the Thirty Years' Peace, the Athenians were instructed not to intervene in the battle unless it was clear that Corinth would invade Corcyra. However, the Athenian ships participated in the battle, and the arrival of additional Athenian [[trireme]]s was enough to dissuade the Corinthians from exploiting their victory, thus sparing much of the routed Corcyrean and Athenian fleet.<ref name=":3" />

Following this, Athens instructed [[Potidaea]] in the peninsula of [[Chalkidiki]], a tributary ally of Athens but a colony of Corinth, to tear down its walls, send hostages to Athens, dismiss the Corinthian magistrates from office, and refuse the magistrates that Corinth would send in the future.<ref name=":3" /> Outraged, the Corinthians encouraged Potidaea to revolt and assured them that they would ally with them should they revolt from Athens. During the subsequent [[Battle of Potidaea]], the Corinthians unofficially aided Potidaea by sneaking contingents of men into the [[Siegecraft in Ancient Greece|besieged]] city to help defend it. This directly violated the Thirty Years' Peace, which stipulated that the Delian League and the Peloponnesian League would respect each other's autonomy and internal affairs.

[[File:Battle of Potidaea 431 BCE.jpg|thumb|[[Battle of Potidaea]] (432 BC): Athenians against Corinthians. Scene of [[Socrates]] saving [[Alcibiades]]. 18th century engraving.]]

A further provocation was Athens in 433/2 BC imposing trade sanctions on Megarian citizens (once more a Spartan ally after the First Peloponnesian War). It was alleged that the Megarians had desecrated the ''[[Hiera Orgas]]''. These sanctions, known as the [[Megarian decree]], were largely ignored by [[Thucydides]], but some modern economic historians have noted that forbidding Megara to trade with the prosperous Athenian empire would have been disastrous for the Megarans, and so have considered the sanctions a contributing causing of the war.<ref name=":2" /> Historians who attribute responsibility for the war to Athens cite this event as the main cause.<ref>{{Cite book |last=Buckley |first=Terry |url=https://www.worldcat.org/title/428731372 |title=Aspects of Greek History 750–323 BC: A Source-Based Approach |date=2010 |publisher=[[Routledge]] |isbn=978-0-415-54976-9 |edition= |series= |location=New York |oclc=428731372}}</ref>

At the request of Corinth, the Spartans summoned members of the Peloponnesian League to Sparta in 432 BC, especially those who had grievances with Athens, to make their complaints to the Spartan assembly. This debate was also attended by an uninvited delegation from Athens, which also asked to speak, and became the scene of a debate between the Athenians and the Corinthians. Thucydides reports that the Corinthians condemned Sparta's inactivity until then, warning Sparta that if it remained passive, it would soon be outflanked and without allies.<ref>{{Cite web |title=Thucydides, History of the Peloponnesian War, THE FIRST BOOK, chapter 68 |url=http://www.perseus.tufts.edu/hopper/text?doc=Thuc.+1.68.1&redirect=true |access-date=26 December 2024 |website=www.perseus.tufts.edu}}</ref> In response, the Athenians reminded the Spartans of Athens's record of military success and opposition to Persia, warned them of confronting such a powerful state, and encouraged Sparta to seek arbitration as provided by the Thirty Years' Peace.<ref>{{Cite web |title=Thucydides, History of the Peloponnesian War, THE FIRST BOOK, chapter 73 |url=http://www.perseus.tufts.edu/hopper/text?doc=Thuc.+1.73.1&redirect=true |access-date=26 December 2024 |website=www.perseus.tufts.edu}}</ref> The Spartan king [[Archidamus II]] spoke against the war, but the opinion of the hawkish ephor [[Sthenelaidas]] prevailed in the [[Ecclesia (Sparta)|Spartan ecclesia]].<ref>{{Cite book |last=De Sainte Croix |first=Geoffrey Ernest Maurice |title=The Origins of the Peloponnesian War |publisher=[[Duckworth Books]] |year=1989 |isbn=978-0-7156-1728-1 |edition= |location=London}}</ref> A majority of the Spartan assembly voted to declare that the Athenians had broken the peace, essentially declaring war.<ref name=":1" />