Geopolitics and the Cause of the Peloponnesian War

Thucydides, and his famous work, The History of the Peloponnesian War, is often misunderstood. Many consider him the so-called father of “objective history,” or “scientific history.” This has never been the position of the philosophers, and at long last that view of Thucydides is changing in history departments too. Thucydides was, as Leo Strauss said, a philosopher of the highest rank; a deeply intellectual person who worked out his philosophy in the pages of a so-called work of history. The owl takes flight only after the events have transpired.


Thucydides gives plenty of episodes as to how the Peloponnesian War came about. There was the most cursory, and incidental, fact that the Spartans broke the treaty they had with the Athenians which prompted a response from Athens that was the nominal reason for the war. But Thucydides is a far deeper thinker than simple cause-effect: Sparta broke the treaty (cause); Athens declared war (effect). There is also the case of Corcyra, the Corcyrean War for Independence against Corinth (cf. I.34-55). Then there is the famous discourse of the representatives of Athens and Sparta at the close of book one (I.66-88). But scattered throughout the rest of the text, Thucydides also makes clear that Athens wanted the war with Sparta to consummate a universal empire that would encompass all Greece, Anatolia, Libya, Sicily, and even Carthage (cf. II.41.4, 62.2-4, 64.3-5, VI.15.2, 34.2, 90.2-3, VII.66.2).

But one of the more immediate causes of the war was geographic. Thucydides is, arguably, the first geopolitical theorist. This should not be surprising, however, given that he is situated in an exciting intellectual time in Athens. Philosophy as we now know it was getting off the ground with veterans of the war, i.e. Socrates. But the pre-Socratic world of philosophy that Thucydides would have been familiar with by simple account of his own intellectual prowess, was a world dominated by elemental philosophy. Thales famously asserted all was water. Anaximenes that all was air. The Ionian metaphysicians were materialists; so too was Thucydides.

This basic elemental, or geographic, metaphysic is visible throughout Thucydides’ history. Athens was the great sea power. Sparta was the great land power. And the alliances forged between the Delian and Peloponnesian leagues followed this central axis of land and sea. Indeed, most of the allies of Sparta were land powers. The inverse was true for Athens, most of her allies were the maritime powers of Greece.

Greece was divided between maritime and continental polities, reflected in the competing alliances of the war. The first outbreak of violence leading to the broader war was between these two opposing geographical realities. Corcyra, although a Corinthian colony, was the second greatest maritime city-state in Greece. When the Corcyraean representatives implored Athens to side with them, they remarked, “The Hellenes have only three fleets that are worthy of mention, yours, ours, and that of the Corinthians; if, now, the Corinthians shall seize us first and you thus let two of these fleets become united, you will have to fight on the sea against both Corcyraeans and Peloponnesians at once; but if you accept us, you will be able to contend against them with your navy augmented by our own.” And just prior to their exhortation of a beneficial sea-alliances, the Corcyraeans, sensing the impulses of Athens’ dream for a larger maritime empire, noted, “Corcyra is favourably situated for a coasting voyage either to Italy or Sicily.”

The Corinthians, one of the unique hybrid powers that was both a potent sea and continental force, nevertheless showed their essential landed character. Their arguments relay on the law of master and slave, a relationship that only exists on land. It was an issue that did not matter to Athens and was, properly, a matter related to a master and his slave; Corinth was the mother city of Corcyra which was a Corinthian colony. But the temptations of a sea-power alliance with Corcyra was too much for Athens to pass up.

In the elemental dialectic of land and sea, land acts as the barrier to sea-power. Corinth was not merely a close neighbor of Athens, she was a literal wall against Athenian ambitions. As was Sparta and the anti-Athenian, which was an anti-maritime, alliance. The sea, Athens, wanted to expand out. She was like the tide rising. Sparta, and her proxy ally Corinth, stood in the way of Athenian expansionist ambitions.

And here is another point highlighted by Thucydides. Corcyra acknowledges that her prior isolationism was wrongheaded. Sea powers cannot remain isolationist; sea powers are inherently expansionist and internationalist. Sea powers need the ports of other nations to sustain themselves. In this way Corcyra was more fully embracing her maritime nature by allying with Athens which, in turn, served to benefit the great sea power of Greece.

For this reason, the war was set in motion. It was a confrontation of land and sea; sea encroaching up against the wall that was the landed alliance led by Sparta. The speech by the Athenian representatives to the Spartans excessively emphasizes the maritime nature of Athens, especially in the context of the Persian Wars. Athens’ dream of empire in Libya, Sicily, and even Carthage, needed to be facilitated by maritime prowess and access. Even the infamous Melian Dialogue, that case-study in international realism, retains—it is actually front and center—this geopolitical dynamic. Melos, an island sea-power, was in the natural orbit of Athens and should, like the other maritime powers of Greece, align with Athens. Melian irrationalism, or idealism, was predicated on their not embracing their maritime nature to its natural end: an alliance with Athens rather than the continental power of Sparta.

A careful reading of Thucydides reveals this geographic, geopolitical, dynamic at work. It is at the very heart of the text. And it is, from Thucydides’ perspective, the real cause of the war. We will continue with an examination of Thucydides in the coming days.


*This is part one of a four part series examining Thucydides’ History of the Peloponnesian War. You can find parts two, three, and four by clicking on their respective links.

3 thoughts on “Geopolitics and the Cause of the Peloponnesian War

  1. Pingback: Geopolitics and the Melian Dialogue | Discourses on Minerva

  2. Pingback: Athenian Exceptionalism and Pericles’ Funeral Oration | Discourses on Minerva

  3. Pingback: Corruption of Language and Morality in History of the Peloponnesian War | Discourses on Minerva

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