Today's Passage
This passage describes the complete encirclement of Potidaea in 432 BCE, a crucial event leading to the Peloponnesian War.
Crawley Translation (1910)
The wall on the side of the isthmus had now works at once raised against it, and manned by the Athenians. That on the side of Pallene had no works raised against it. They did not think themselves strong enough at once to keep a garrison in the isthmus and to cross over to Pallene and raise works there; they were afraid that the Potidæans and their allies might take advantage of their division to attack them. Meanwhile the Athenians at home learning that there were no works at Pallene, some time afterwards sent off sixteen hundred heavy infantry of their own citizens under the command of Phormio, son of Asopius. Arrived at Pallene, he fixed his headquarters at Aphytis, and led his army against Potidæa by short marches, ravaging the country as he advanced. No one venturing to meet him in the field, he raised works against the wall on the side of Pallene. So at length Potidæa was strongly invested on either side, and from the sea by the ships co-operating in the blockade. Aristeus, seeing its investment complete, and having no hope of its salvation, except in the event of some movement from the Peloponnese, or of some other improbable contingency, advised all except five hundred to watch for a wind and sail out of the place, in order that their provisions might last the longer. He was willing to be himself one of those who remained. Unable to persuade them, and desirous of acting on the next alternative, and of having things outside in the best posture possible, he eluded the guardships of the Athenians and sailed out. Remaining among the Chalcidians, he continued to carry on the war; in particular he laid an ambuscade near the city of the Sermylians, and cut off many of them; he also communicated with Peloponnese, and tried to contrive some method by which help might be brought. Meanwhile, after the completion of the investment of Potidæa, Phormio next employed his sixteen hundred men in ravaging Chalcidice and Bottica: some of the towns also were taken by him.
Congress of the Peloponnesian Confederacy at Lacedaemon
The Athenians and Peloponnesians had these antecedent grounds of complaint against each other: the complaint of Corinth was that her colony of Potidæa, and Corinthian and Peloponnesian citizens within it, were being besieged; that of Athens against the Peloponnesians that they had incited a town of hers, a member of her alliance and a contributor to her revenue, to revolt, and had come and were openly fighting against her on the side of the Potidæans. For all this, war had not yet broken out: there was still truce for a while; for this was a private enterprise on the part of Corinth.
Modern Translation
The Athenians had immediately constructed and manned fortifications on the isthmus side of the wall. However, they built no fortifications on the Pallene side, as they didn't believe they had sufficient forces to both maintain a garrison on the isthmus and cross to Pallene to construct defenses there. They feared that dividing their forces would leave them vulnerable to attack by the Potidaeans and their allies. When the Athenians back home learned that the Pallene side remained unfortified, they dispatched sixteen hundred of their own heavy infantry under Phormio, son of Asopius. Upon reaching Pallene, Phormio established his base at Aphytis and advanced toward Potidaea in measured stages, devastating the countryside along the way. Since no one dared to face him in open battle, he constructed siege works against the wall on the Pallene side. Thus Potidaea found itself completely blockaded on both land approaches, while Athenian ships enforced the siege from the sea. Aristeus, recognizing that the siege was complete and seeing no hope of salvation except through some unlikely intervention from the Peloponnese or other improbable event, proposed that all but five hundred defenders should wait for favorable winds and sail out, thereby extending the provisions for those remaining. He offered to stay himself among the five hundred. When he couldn't convince them, and wanting to make the best of the situation from outside, he slipped past the Athenian patrol ships and escaped. He remained with the Chalcidians, continuing military operations—notably ambushing and killing many Sermylians near their city. He also maintained communications with the Peloponnese, attempting to arrange reinforcements. Following the complete investment of Potidaea, Phormio led his sixteen hundred troops in devastating raids throughout Chalcidice and Bottica, capturing several towns in the process.
Congress of the Peloponnesian Confederacy at Lacedaemon
The Athenians and Peloponnesians thus had accumulated grievances against one another: Corinth complained that Athens was besieging her colony Potidaea along with Corinthian and Peloponnesian citizens trapped inside; Athens countered that the Peloponnesians had encouraged a member of her alliance and a revenue-contributing city to rebel, and had come to fight openly alongside the Potidaeans. Despite these provocations, war had not yet officially begun—a fragile peace still held, as Corinth's involvement was technically a private undertaking.
Historical Context
This passage describes the complete encirclement of Potidaea in 432 BCE, a crucial event leading to the Peloponnesian War. The Athenians, initially unable to fully blockade the city, receive reinforcements under the capable general Phormio, who completes the siege by fortifying the Pallene approach. The Corinthian commander Aristeus, recognizing the hopelessness of the situation, escapes to continue resistance from outside. Thucydides emphasizes how both sides accumulated grievances while technically maintaining peace—Athens angry at Peloponnesian support for their rebellious ally, Corinth furious at the siege of their colony. This delicate situation, where hostile actions occurred under the fiction of private enterprise, illustrates the breakdown of the Thirty Years' Peace and the slide toward inevitable war.
Key Themes
Annotations & References
Siege Warfare
Ancient Greek siege warfare typically involved circumvallation—building walls around a besieged city to prevent escape or resupply. Potidaea's position on an isthmus made it particularly challenging, requiring fortifications on two land approaches plus naval blockade. Such sieges were expensive, time-consuming operations that could last years.
Learn more →Phormio
Phormio was one of Athens' most capable generals, later famous for his naval victories in the Gulf of Corinth. His methodical approach at Potidaea—establishing a secure base, advancing carefully while devastating enemy territory—demonstrates the professional competence of Athenian military leadership in this period.
Learn more →Chalcidian League
The Chalcidians mentioned were Greek cities on the Chalcidice peninsula who had formed a confederation in opposition to Athenian power. Their alliance with Potidaea represented a significant challenge to Athenian control in the strategically vital northern Aegean region.
Learn more →Parallel Ancient Sources
Diodorus Siculus: Library of History (12.34)
Diodorus provides a parallel account of the Potidaea siege, offering additional details about the cost and duration of the operation, though his chronology sometimes differs from Thucydides.
Read passage →Plutarch: Life of Pericles (23-24)
Plutarch discusses the financial burden of the Potidaea siege on Athens and its role in undermining Pericles' political position, providing insight into the domestic consequences of this military commitment.
Read passage →Xenophon: Hellenica (2.2.3)
Though writing about a later period, Xenophon describes similar siege operations that illuminate standard Greek military practices, including the use of circumvallation and the challenges of maintaining long blockades.
Read passage →Discussion Questions
- How does Thucydides' description of 'private enterprise' by Corinth illustrate the breakdown of international law and custom before the war?
- What does Aristeus's escape and continued resistance suggest about the nature of leadership and personal honor in Greek warfare?
- How might the Athenian decision to complete the blockade despite resource constraints reflect imperial overextension?
- In what ways does the siege of Potidaea exemplify the economic and strategic calculations that drove Greek interstate conflict?