The Peloponnesian War summary

For three decades at the end of the fifth century BC, two empires collided: Athens and Sparta. It was a war unlike any that had come before. Previously, massive armies lined up in orderly rows and files had crashed into each other in large fields. One side would be declared the winner, and that was that.

The Peloponnesian War was different. It was fought largely on water, where the more experienced naval empire of Athens had the advantage. But it was also a war of insurgents, where allies on both sides were vulnerable to rebellions that resulted in violent uprisings and prolonged sieges. In short, it changed the rules of warfare in ways that are still relevant today.

In these blinks, you’ll learn

• how the war escalated from a civil war in a place many had never heard of;
• how a debacle in Sicily broke the peace between Athens and Sparta; and
• which general spent time working for Athens, Sparta, and Persia.

Some historians have seen parallels between the Peloponnesian War and World War I. For starters, both of these epic conflicts were sparked by seemingly minor events that took place in relatively obscure parts of the world.

In the case of Athens and Sparta, that small and remote area was Epidamnus, a city so far north along the shores of the Adriatic Sea, that few Athenians had ever heard of it. In 436 BC, Epidamnus fell into the grips of civil war and the democrats within the city sent for help to their founders in Corcyra, a city on the island of Corfu. When Corcyra refused to help, the problem soon spiraled out of control.

The key message here is: Events in Epidamnus set the stage for a much bigger conflict.

There’d been other threats to peace between Athens and Sparta, but few would have predicted that the issue that would tip the scales would be a civil war in Epidamnus. But once Corcyra refused to step in, the Epidamnians reached out to Corinth.

Here it gets a bit complicated. Corcyra had actually been founded by Corinthians, but since then the relationship between the two states had soured. So, the Corinthians jumped at the chance to swoop in and save a colony that Corcyra was choosing to ignore. And Corinth not only stepped in, it established a garrison and announced the establishment of an entirely new colony.

Understandably, Corcyra wasn’t too happy about this, and it wasn’t a powerless state, either. With 120 warships at its disposal, it had one of the biggest fleets in the region at the time. Corinth, on the other hand, wasn’t only a force to be reckoned with in its own right, it was also an ally in the Peloponnesian League, so it could rely on some backing from Sparta.

Initially, Sparta didn't want to get involved, but when it became apparent Corcyra might turn to Athens for support, it stepped in and efforts were made to find a peaceful solution. But by this point, the Corinthians had asserted themselves too far to just back down. They rejected Corcyra’s proposal to engage in mutual withdrawal. Instead, Corinth declared war on Corcyra.

Corinth may have underestimated Corcyra’s strength. A fleet of 75 Corinthian ships was routed by Corcyrean forces. Still, the Corinthians didn’t back down. Instead, they got to work on building an even bigger fleet. Then, Corcyra made the fateful decision to seek an alliance with Athens.

When word got out that Corcyrean ambassadors were traveling to Athens, Corinth quickly sent its own people to present its side of the conflict. In September of 433 BC, each side was heard by the full Athenian assembly.

One of Corinth’s main arguments was that Athens shouldn’t get involved due to the treaty between Sparta and Athens, known as the Thirty Years’ Peace. The Corcyrean ambassadors, on the other hand, pointed out that the treaty did allow for any autonomous city to align itself with Athens or Sparta, if it so wished. So, technically, Athens was free to sign a pact with Corcyra

Outraged, the Corinthians made it clear that, if that were to happen, they would make Athens their enemy.

The key message here is: With aggressions rising, Athens and Sparta moved closer to war.

The Athenian assembly took an extra day to deliberate. And, for the first time in recorded Greek history, Athens decided on a purely defensive alliance. It wouldn’t participate in any attacks on Corinth, but rather only help defend Corcyra, if necessary.

With this move, the Athenians were really aiming for deterrence and non-aggression. They were hoping the alliance would prevent further conflict. Or, if there was another battle, that Corcrya would once again prevail on its own. Alas, in the Battle of Sybota, which followed shortly after the negotiations, Athens was needed – because this time, Corcrya was nearly routed by Corinth. But when Athenian reinforcements arrived, the Corinthian fleet backed off and sailed back home.

At this point, Sparta and the Peloponnesian League were still on the sidelines, not eager to get involved in any Corinthian aggression. But things began to change. In Potidea, a city that had been founded by Corinth and yet was part of the Athenian League, an uprising of pro-Corinthian rebels was likely sparked by Spartan ephors promising support.

And then there was the Megarian Decree. Megara, which sits between Corinth and Athens, had helped Corinth in the Battle of Sybota and was charged by Athens with encroaching upon borderlands and harboring fugitive slaves. The Megarian Decree was essentially an embargo, prohibiting Megara from utilizing harbors within the Athenian Empire.

Naturally, Megara protested this embargo. There were now two members of the Peloponnesian league which had very vocal grievances against Athens. Sparta could no longer sit idly by. In July 432 BC, a Spartan assembly listened to these grievances. Afterward, they listened to an Athenian ambassador. A decision had to be made.

At the start of the war, Athens and Sparta each had a voice of moderation and reason in key positions of power. Athens had Pericles, a heroic veteran of the Persian War whose bloodline could be traced back to the very first founders of Athenian democracy. He was a confident and beloved leader, and one of the most respected orators and politicians in Greek history. Sparta, on the other hand, had Archidamus, who wasn’t only one of Sparta’s two kings but also a personal friend of Pericles.

Neither Pericles nor Archidamus wanted to throw aside 30 years of peace. They both knew that a war wouldn’t be won easily by either side. In fact, Archidamus was quite prescient. After the July assembly, he believed that if there were a war, it wouldn’t be over in their lifetimes.

The key message here is: After failed ultimatums, the war began in 431 BC.

Despite Archidamus’ forebodings, many in the assembly felt that Athens’s imperial ambitions were getting out of hand. As they saw it, Athens was using conflict to increase its power. Sparta, they argued, needed to stand by its allies or else risk losing them.

Sparta first issued an official complaint against Athens while quietly preparing for war. Then came a period of tense back and forth negotiations between the two Greek powers. On different occasions, Sparta gave Athens ultimatums that would supposedly prevent war. On at least one occasion, it was to “give the Greeks their autonomy,” which really meant dismantling the Athenian Empire. But on more than one occasion, the ultimatum rested upon removing the Megarian Decree.

For many Athenians, this seemed like a fair enough concession to avoid war. But Pericles was convincing in his reasons for rejecting Sparta’s demand. Most of all, Pericles wanted Sparta to adhere to the treaty behind the Thirty Years’ Peace, which stated that any disputes would be subject to arbitration. For this reason, he rejected any ultimatum. He also believed that once Athens agreed to one Spartan demand, it would only set a dangerous precedent, leading to further demands.

There’s good reason to believe that Pericles was right. At the heart of Sparta’s concerns were Corinthian threats to break away from Sparta if action wasn’t taken, and making the Megarian Decree the only demand would be leaving Corinth without satisfaction.

In the end, Sparta didn’t agree to arbitration, even though it was part of the treaty, and Athens didn’t accept any ultimatums. With little choice left, war erupted, with the first attack against Athens coming in March 431 BC from Sparta’s allies, the Thebans.

After the decision had been made to go to war, Athens adopted an unusual strategy. Devised by Pericles, the plan was a largely defensive one, designed to show Sparta that Athens was impervious to its aggression. Essentially, Athens would rely on its fortified walls to protect the city, and on its superior fleet and far more experienced rowers and naval crew to protect its interests and allies.

Pericles knew that the Spartan army was superior on land – and Sparta believed that this war, like previous ones, would be decided through traditional battles on land – but this war would be different. Athens would keep the fight primarily on the water, and Pericles thought that it would just be a matter of time before Sparta would recognize they didn’t stand a chance. As it turned out, neither side was right.

The key message here is: Athens began the war with a defensive strategy, but it didn’t play out how it had imagined.

For the first couple of years, Pericles’s strategy was more or less successful. The Spartan army raided Attica, the peninsula on which Athens was situated, but Athens’s cavalry was able to keep the attackers at bay until their provisions ran out and they were forced to return home.

Athens even made some early gains, capturing a few cities that were of strategic importance to the Peloponnesian League. But the hard facts at the end of the first year weren’t great. Athens did nothing to weaken Sparta, while the Spartan raid on Attica did destroy many valuable vineyards, crops, and olive trees.

The following year, Pericles already saw the need to be more aggressive. But he also had other, pressing concerns, which complicated matters. A plague was spreading through Athens, which was now crowded by rural families seeking shelter from the war. It took as much as a third of the population before it was finished. Plus, the cost of maintaining a large naval fleet was quickly depleting the city’s reserves. It wasn’t long before Pericles’s rivals were putting on the pressure to come up with a new plan.

They didn’t have to wait long. By the end of the third year of war, Pericles had died. No one in the city who could match his stature and so unite the people. But two men, Nicias and Cleon, stepped up with two very different strategies. Nicias fought for peace, while Cleon rejected the very notion of compromise and wanted nothing short of total victory. Either way, Pericles’s defensive strategy was a thing of the past.

The days of two armies squaring off in an open field were over. The Peloponnesian War was a different affair. In many cities, citizen-soldiers took up arms to fight on the side of democracy or Spartan-friendly oligarchs, depending on which way the tide of the war was turning.

Gone too were many of the traditional conventions of warfare, especially around the taking of prisoners. On both sides, prisoners were executed, and women were sold into slavery. But these were far from the biggest atrocities to occur as the war raged on.

The key message here is: The war was a brutal affair, but after a key victory by Athens, a period of peace arrived.

Many cities fell into chaos as the balance of power shifted back and forth between Athens and Sparta during the war. There was no sense of security, and cities acted in their own self-interests, inciting rebellions in the hope of being protected by Athens or Sparta.

Four years into the war, in 427 BC, the people of Mytilene rebelled against Athens and 1,000 men deemed “most guilty” were executed without trial. This was a compromise – Cleon had initially wanted all the men who took part to be killed. Such compromises didn’t always prevail.

Two years later, the hope of peace did arrive, thanks to the ambitious plotting and strategic ingenuity of Athenian general Demosthenes. Around 425 BC, he began crafting a plan that involved establishing a base at a strategic spot known as Pylos, on the coast of Messenia. The idea was that it would give Athens a good place to launch attacks on Spartan interests.

The fortifications at Pylos set the stage for a stunning naval victory for Athens and Demosthenes. It was a route that essentially ruined the Spartan fleet and ended with the capture of 292 Spartans – among them 180 Spartiates, some of the most elite members of Spartan society. There was an immediate call for a truce, and for the first time since the war had begun, negotiations were underway.

At first, Athens sought to find a way to turn this morale boost into total victory. But its luck ran out the following year when Sparta took Amphipolis, a source of timber and valuable materials for Athens. While trying to regain its losses, Cleon, the constant pro-war voice in Athens, was killed in battle. This set the stage for Nicias’s call for peace to finally gain traction. And so, on March 12, 421 BC, the “Peace of Nicias” was ratified.

With the Spartan hostages as an important bargaining chip, Athens and Sparta were able to agree on terms for peace. In reality, neither side had been able to shift the balance of power over ten years of fighting. But although peace had been agreed, there was no shortage of ill will.

This was especially the case among some of the more influential allies, like Sparta’s allies in Thrace, who refused to give up the hard-won city of Amphipolis, even though this was a key point in the treaty. So, right from the beginning, there were signs that peace wasn’t going to last.

The key message in this blink is: The treaty remained for over five years, but it was undermined by a disaster in Sicily.

One of the most dangerous threats to peace was Argos, a large city north of Sparta and south of Corinth. Not long after the treaty was ratified, Argos began plotting and putting together the Argive League, a coalition separate from the Peloponnesian League. The Matineans quickly joined the Argive League, followed by the Eleans.

This led to the Battle of Mantinea, which Sparta won, and it brought a brief reign of oligarchic terror to Argos. Amidst this turmoil, new war hawks appeared in Athens, led by the influential voice of Hyperbolus, who eventually ended up being ostracized from Athens. But it was events in Sicily that finally drove Athens and Sparta back to war.

The debacle in Sicily has drawn comparisons to the US involvement in Vietnam. Around the end of 416 BC, Athens received a request for help from Segesta and Leontini, two long-held allies on the island of Sicily. In particular, Leontini was in danger of being taken over by another Sicilian city, Syracuse. However, like Vietnam, the Sicilian campaign began badly and only got worse the more committed Athens became to finishing it.

Ironically enough, Nicias’s decisions can be seen as being responsible for much of what went wrong. Not wanting Athens to embark on the campaign to begin with, Nicias tried to dissuade voters by claiming that an enormous armada would be required for success. The Athenian assembly not only agreed with him, they put him in charge.

Crucially missing from Nicias’s initial armada, which launched in March 415 BC, was cavalry – likely because he still believed engagement could be avoided. As a result, an early opportunity for victory was lost when Athens stormed the Syracusian aggressors, had them on the run, but were unable to finish them off.

Instead, Syracuse was able to reach out to Sparta for reinforcements, which led to a catastrophic defeat, with 7,000 Athenian prisoners killed after being kept captive for months in stone quarries.

With Athenian and Spartan forces clashing in Sicily, the truce was officially over. Efforts at sparking uprisings throughout the region resumed and alliances were once again being made and broken.

After Sicily, a new player emerged: Persia. For a while, the former enemy of both Athens and Sparta was sitting on the sidelines, hoping the two combatants would wear each other down. But after Athens’s severe losses to Sicily, where both Nicias and Demosthenes were killed, Persia’s Great King Cyrus began to bet on Sparta by funding the construction of its warships.

The key message here is: With Persia backing Sparta, Athenian democracy came under threat.

For some time, the lure of Persian assistance was strong for some Athenians. In fact, it was one of the motivating factors behind a coup that temporarily overthrew the Athenian government in 411 BC.

One of the figures behind the scenes of this coup was Alcibiades, one of the more colorful characters to have served as general during the war. He’d competed at the Olympic Games and was so good looking and charismatic that he had both men and women chasing after him. He was also admired for his intelligence, and so he’d served as an elected general multiple times.

In fact, he had been one of the generals to accompany Nicias on the doomed voyage to Sicily. But at the time he had serious charges of blasphemy hanging over his head. To avoid a possible death sentence, Alcibiades fled to Sparta. From there he became a confidant to Tissaphernes, a Persian satrap, or governor.

When Alcibiades passed along the idea that Persia may support Athens, on the condition that democracy was abandoned in favor of oligarchic rule, the wheels were set in motion for a coup. Even when it became clear that Alcibiades’s information may not have been entirely truthful, or that Tissaphernes’s offer was sincere, it was too late.

A group known as the Four Hundred took control of the government in Athens, under the guise of making only moderate reforms that would divert funds away from democratic public service. Money was needed to continue the war, but the Four Hundred had no intention of restoring any democratic functions.

Word soon got out that the members of the coup were ready to give up Athens in exchange for peace and their own safety. Rumors of a Spartan fleet heading to Athens caused an uprising and the members of the coup were charged with treason. One escaped, but three others were executed.

Oddly enough, when democracy was fully restored, the people were ready to welcome back a charismatic but controversial figure: the duplicitous Alcibiades.

The Athenians needed a new hero. So they turned to Alcibiades, who’d proven ambitious and bold in his planning. They didn’t know of his involvement in the early stages of the coup, and for his part, Alcibiades likely never gave up his love for Athens. So when the people welcomed him back, he wanted to provide them with a great victory before he set foot back in the city. He also had good reason to fear that some in the city may not be so happy to see him.

In fact, it was four years before Alcibiades returned in 407 BC, and he did arrive after a series of victories in the Hellespont region, taking the city of Selymbria and bringing the important gateway city of Byzantium back into Athenian hands.

The key message here is: After a regrettable defeat, Athens had a final grand victory marred by tragedy.

Alcibiades’s grand return was short-lived. He took 80 ships to confront Lysander, the Spartan admiral who controlled 90 ships at Ephesus. Lysander was proving difficult to lure out into open water, and Alcibiades made the mistake of leaving his fleet in the hands of his friend Antiochus, while he went to visit a general, who was leading a siege on a nearby city.

While Alcibiades was away, Antiochus attempted to attack Lysander himself, leading to a terrible defeat. Alcibiades subsequently fled to Gallipoli in disgrace.

But Athens had one more victory to serve the Spartans. At the Battle of Arginusae, an inexperienced crew of hastily assembled Athenians was able to defeat a Spartan fleet with unorthodox tactics. Sparta lost 77 ships, but the victory was marred by the fact that the disorganized Athenian fleet failed to recover its lost and dead crewmates after the battle had ended.

Back in Athens, there was a vote, and with tensions running high, the eight generals in charge of the Athenian fleet at the Battle of Arginusae were executed for this oversight. Many Athenians later regretted this decision, and it left the whole city with low morale and with very few experienced generals.

Further compounding the problem was the fact that Sparta was being bankrolled by Persia. So it was able to quickly rebuild its fleet to even bigger numbers. This set the stage for the final showdown at Aegospotami.

At Aegospotami, Lysander was back in charge of the Spartan fleet. He was the favorite admiral of the Persian Great King Cyrus, and Lysander wisely chose the location of the battle. Aegospotami was situated in an area with no harbor. Once more, Lysander was going to deny Athens the open water in which to outmaneuver its opponent.

Athens was again stuck, trying to lure Lysander out. Amazingly, Alcibiades showed up and tried to offer the inexperienced Athenian generals some advice. It seems he had a view of the standoff from his residence in Gallipoli. He advised the Athenian fleet to back off and use the nearby base in Sestos to wait Lysander out. As it stood, the Athenians were beaching many of their ships and had no safe supply of food and resources. Who knows what would have happened if they’d taken his advice.

The key message in this blink is: Athens lost the war, but with amazing resolve its democratic spirit stayed alive.

Alcibiades also suggested he could wrangle up a number of Thracians to attack Lysander by land and force him out. This could have been another of his less than truthful claims, but it didn’t matter. No general was willing to make a decision associated with the disgraced Alcibiades. Instead, one general decided to send out just 30 ships to lure Lysander into battle.

It seems this maneuver caught the other generals off guard. If it was meant to be a coordinated maneuver it failed. The 30 ships were routed by Lysander and many in the rest of the Athenian fleet were beached and slow to respond. Only ten ships from the entire Athenian navy survived and thousands of crew were captured and killed. It was the end of the war for Athens.

Immediately, Athens’s allies were threatened with death if they sent any food or supplies to the city. Sparta intended to starve Athens into submission. At first, any negotiations for anything other than total annihilation were rejected. Sparta wanted the walls of Athens to fall and for the city to give itself over completely. Athens refused.

Months went by until a sliver of hope came from Theramenes, one of the men who had helped restore democracy after the days of the Four Hundred. After a painfully prolonged three months of negotiations between Theramenes and Lysander, Athens was given the option of avoiding death and destruction if it took down its walls, handed over the remainder of its fleet, and allowed an oligarchy to take over the government.

Realizing it was the best they could possibly hope for, the Athenians agreed. Remarkably, it enabled them to survive. A former general, Thrasybulus, was able to escape and form a small army that hid in the mountains outside Athens. Eventually, thanks to Thrasybulus’s efforts, the enemies of democracy were rooted out. This time, only a few of the worst criminals were punished. It was time to start with moderation, restraint, and a spirit of amnesty. With this, the stage was set for the Second Athenian Empire to flourish.