The History of the Peloponnesian War tells the story of the Peloponnesian War in Ancient Greece. It was written by Thucydides, an Athenian general who served in that war. The war was fought between the Peloponnesian League (led by Sparta) and the Athenian league (led by Athens). The war lasted more than 20 years.

Many historians regard this History of  Thucydides as one of the earliest scholarly works of history.

Historical method
Thucydides' History made a number of contributions to early historiography. Many of his principles have become standard methods of history writing today, though others have not.

Chronology
One of Thucydides' major innovations was to use a strict standard of chronology, recording events by year, each year consisting of the summer campaigning season and a less active winter season. As a result, events that span several years are divided up and described in parts of the book that are sometimes quite distant from one another, causing the impression that he is oscillating between the various theatres of conflict. This method contrasts sharply with Herodotus' earlier work The Histories, which jumps around chronologically.

Speeches
Another feature of the work is that Thucydides writes dozens of speeches of the most important figures who were engaged in the war. Thucydides heard some of these speeches himself but some of the speeches he wrote without knowing exactly what was really spoken.

Neutral point of view
Thucydides wanted his writings "to last for ever" (1.22.4). Therefore he tried to be as neutral as possible though as general of Athens that was difficult for him.

Role of religion
The gods play no active role in Thucydides' work. This is very different to Herodotus, who frequently mentions the role of the gods. Instead, Thucydides regards history as being caused by the choices and actions of human beings.

The History concentrates on the military aspects of the Peloponnesian War, but it uses these events as a medium to suggest several other themes as well, for instance to show degenerative effects of war on humanity itself. 
For the most part, the History does not discuss topics such as the art and architecture of Greece, but speaks of the development of military technologies
rather often. 

The History explains that the cause of the Peloponnesian War was the "growth in power of Athens, and the alarm which this inspired in Sparta" (1.23.6). The Spartans represent a more traditional and less expansive power.

Sources
Thucydides almost never names his informants. This is in contrast to Herodotus, who frequently mentions multiple versions of his stories and allows the reader to decide which is true.

Influence
Thucydides' History has been enormously influential in both ancient and modern historiography.

Outline of the Work

Book 1
The state of Greece from the earliest times to the commencement of the Peloponnesian War, also known as the Archaeology. 1.1-1.19.
Methodological excursus. 1.20-1.23.
Causes of the war (433-432 BCE) 1.24-1.66.
The Affair of Epidamnus. 1.24-1.55.
The Affair of Potidaea. 1.56-1.66.
Congress of the Peloponnesian League at Lacedaemon. 1.67-1.88
The Speech of the Corinthians. 1.68-1.71.
The Speech of the Athenian envoys. 1.73-1.78.
The Speech of Archidamus. 1.80-1.85.
The Speech of Sthenelaidas. 1.86.
From the end of the Persian War to the beginning of the Peloponnesian War, also known as the Pentacontaetia. 1.89-1.117.
The progress from supremacy to empire.
Second congress at Lacedaemon and the Corinthian Speech. 1.119-1.125.
Diplomatic maneuvering. 1.126-1.139.
Excursus on Cylon. 1.126-1.127.
Excursus on Pausanias and Themistocles. 1.128-1.138
Pericles' first speech. 1.140-1.145.
Book 2 (431-428 BCE)
War begins with Thebes' attempt to subvert Plataea. 2.1-2.6.
Account of the mobilization of and list of the allies of the two combatants. 2.7-2.9.
First invasion of Attica. 2.10-2.23.
Archidamus leads the Peloponnesian army into Attica. 2.10-2.12.
Athenian preparations and abandonment of the countryside. 2.13-2.14.
Excursus on Athenian synoikism. 2.15-2.16.
Difficult conditions in Athens for refugees from countryside. 2.17.
Archidamus ravages Oenoe and Acharnai. 2.18-2.20.
Athenian fury and anger at Pericles. 2.21-2.22.
Athenian naval counter-attacks along coast of Peloponese and islands. 2.23-2.32.
Pericles' Funeral Oration. 2.34-2.46.
The plague of Athens. 2.47-2.54.
Second invasion of Attica and Athenian naval counter-attacks. 2.55-2.58.
Pericles' third speech, defending his position and policy. 2.59-2.64.
Thucydides' estimate of Pericles' qualities and the causes for Athens' eventual defeat. 2.65.
Diplomacy and skirmishes in Thrace, the islands, and the Northeast. 2.66-2.69.
Fall of Potidaea. 2.70.
Investment of Plataea. 2.71-2.78.
Naval victories of Phormio in the Northeast. 2.80-2.92.
Threat of raid on the Piraeus. 2.93-2.94.
Thracian campaign in Macedonia under Sitalces. 2.95-2.101.
Book 3 (428-425 BCE)
Annual invasion of Attica. 3.1.
Revolt of Mytilene. 3.2-3.50.
Speech of Mytilenian envoys to Sparta at Olympia, asking for help. 3.9-3.14.
Sparta accepts Lesbos as an ally and prepares to counter the Athenians. 3.15.
Mytilene surrenders to Athens despite Spartan support. 3.28.
Mytilenian Debate. 3.37-3.50.
Fall of Plataea. 3.20-3.24, 3.52-68.
Some Plataeans escape. 3.20-3.24.
Plataea surrenders. 3.52.
Trial and execution of the Plataeans. 3.53-3.68.
Speech of Plataeans, 3.53-3.59.
Speech of the Thebans. 3.61-3.67.
Revolution at Corcyra. 3.70-3.85.
Thucydides' account of the evils of civil strife. 3.82-3.84.
Athenian campaigns in Sicily. 3.86, 3.90, 3.99, 3.103, 3.115-3.116.
Campaigns of Demosthenes in western Greece. 3.94-3.98, 3.100-3.102, 3.105-3.114.
Spartans establish Heracleia in Trachis. 3.92-3.93.
Athenians purify Delos. 3.104.
Book 4 (425-423 BCE)
Annual invasion of Attica. 4.2.
Athenians en route to Sicily occupy Pylos in the Peloponnese. 4.2-4.6.
King Agis of Sparta cuts short the invasion of Attica to return to the Peloponnese. 4.6.
Concerted Spartan attack on the Athenian fort at Pylos. 4.8-4.15.
The Athenian general Demosthenes coordinates the defense of Pylos and rouses the troops with a speech. 4.9-4.10.
The Spartan commander Brasidas distinguishes himself for bravery. 4.11-4.12.
The Athenians defeat the Spartan assault on Pylos and cut off a garrison of Spartiates on the adjacent island of Sphacteria. 4.13-4.14.
The Spartans, concerned for the men on the island, conclude an immediate armistice and send an embassy to Athens to negotiate peace. 4.13-4.22.
The speech of the Spartan ambassadors offers to peace and alliance to Athens in exchange for the return of the men on Sphacteria. 4.17-4.20.
The Athenian Cleon, speaking in the Assembly, encourages the Athenians to demand the return of the territories surrendered by Athens at the conclusion of the First Peloponnesian War. 4.21-4.22.
Events in Sicily. 4.24-4.25.
Siege of the Spartiates on Sphacteria continues without result. 4.26-4.27.
Cleon takes command at Pylos. 4.27-4.29.
With the siege of Sphacteria yielding no results, the Athenians grow angry at Cleon for encouraging them to reject the Spartan offer of peace. 4.27.1-.4.27.3.
Cleon blames Nicias and the generals for ineptitude. 4.27.5.
Nicias yields command to Cleon. 4.28.
Battle of Sphacteria results in the capture of all the Spartiates trapped there. 4.29-4.41.
Nicias leads an Athenian attack on Corinth. 4.42-4.45.
End of Corcyraean revolution. 4.46-4.48.
Athenians capture Cythera, an island off the Peloponnese, and Thyrea, a town in the Peloponnese.  Sparta is hemmed in on all sides and desperate. 4.53-4.57.
Sicilian cities make peace in conference at Gela, frustrating Athenian designs on the island. 4.58-65.
Speech of Hermocrates at Gela. 4.59-4.64.
Athenian attack on Megara. 4.66-4.74.
Capture of Nisaea. 4.69.
Inconclusive engagements at Megara. 4.73.
Megara eludes Athenian capture. 4.74.
Invasion of Boeotia. 4.76, 4.89-4.101.2.
Athenians occupy temple at Delium. 4.90.
Battle of Delium results in Athenian retreat. 4.91-4.96.
Boeotians refuse to return Athenian dead until Athenians relinquish the shrine of Delium. 4.97-4.99.
Boeotians assault the Athenian in the temple and burn it down. 4.100.
Brasidas marches through Thessaly to Thrace and begins to cause Athenian subject cities to revolt. 4.78-4.88.
Speech of Brasidas to the Acanthians. 4.85-4.87.
Fall of Amphipolis to Brasidas. 4.102-4.108.
Continued successes of Brasidas in Thrace. 4.111-4.135.
Brasidas secures the revolt of the garrison of Torone. 4.110-4.116.
One-year armistice between Athenians and Spartans. 4.117-4.118.
Scione revolts from Athens to Brasidas. 4.120-4.123.
Truce breaks down. 4.122-4.123.
Athenians retake Mende and besiege Scione. 4.129-4.131.
Book 5 (422-415 BCE)
Death of Cleon and Brasidas
Peace of Nicias
Feeling against Sparta in the Peloponnese
League of the Mantineans, Eleans, Argives, and Athenians
Battle of Mantinea and breaking up of the League
The Melian Dialogue
Fate of Melos
Book 6 (415-414 BCE)
The Sicilian Expedition
Affair of the Hermae
Departure of the expedition to Sicily
Parties at Syracuse
Story of Harmodius and Aristogiton
Disgrace of Alcibiades
Inaction of the Athenian army
Alcibiades at Sparta
Investment of Syracuse
Book 7 (414-413 BCE)
Arrival of Gylippus at Syracuse
Fortification of Decelea
Successes of the Syracusans
Arrival of Demosthenes (general)
Defeat of the Athenians at Epipolae
Folly and obstinacy of Nicias
Battles in the Great Harbour
Retreat and annihilation of the Athenian army
Book 8 (413-411 BCE)
Revolt of Ionia
Intervention of Persia
The war in Ionia
Intrigues of Alcibiades
Withdrawal of the Persian subsidies
Oligarchical coup d'état at Athens
Patriotism of the Athenian army at Samos
Recall of Alcibiades to Samos
Revolt of Euboea and downfall of the Council of the Four Hundred
Battle of Cynossema

Notes

Internet Sources

Secondary Sources
 Connor, W. Robert, Thucydides. Princeton: Princeton University Press (1984). .
 Hornblower, Simon, A Commentary on Thucydides. 2 vols. Oxford: Clarendon (1991-1996).  (vol. 1),  (vol. 2).
 Hornblower, Simon, Thucydides. London: Duckworth (1987). .
 Orwin, Clifford, The Humanity of Thucydides. Princeton: Princeton University Press (1994).
 Romilly, Jacqueline de, Thucydides and Athenian Imperialism. Oxford: Basil Blackwell (1963). .
 Rood, Tim, Thucydides: Narrative and Explanation. Oxford: Oxford University Press (1998). .
 Strassler, Robert B, ed. The Landmark Thucydides: A Comprehensive Guide to the Peloponnesian War. New York: Free Press (1996). .

Translations
 Thomas Hobbes, 1628: full text
 William Smith, 1753
 Richard Crawley, 1874: full text 
 Benjamin Jowett, 1881: full text 
 Edgar C. Marchant, 1900
 Charles Forster Smith, 1919
 Rex Warner, 1954
 John H. Finley, Jr., 1963
 Walter Blanco, 1998

Wars involving Europe
Ancient Greece