The duration of the Peloponnesian War was a hard time to be an Athenian. From the outset, Spartan raids on the Athenian countryside forced people to crowd into the city, where squalid conditions soon led to a catastrophic plague epidemic. Largely deprived of the produce from their own farms, Athenians relied for their food supply on imports brought down a precarious lifeline from the Black Sea. Aware that they were no match for the Peloponnesian army in pitched battle, they were forced to endure the systematic destruction of their farms while constantly worrying over the possible revolt and defection of their subjects across the sea.

During the first phase of the war, called the Archidamian War (431-421 BC) after the Spartan king Archidamos, Sokrates served as a hoplite in several campaigns. He took part in the long siege of Potidaia on the Thracian Chersonese - a siege that dragged on through a bitter winter, in which Sokrates impressed and disgusted his comrades by his stoic display of indifference to the freezing cold. Some years later, he took part in the Delion campaign, an abortive attempt to subdue the Boiotians, who were allies of Sparta. The battle of Delion (424 BC) ended in terrible defeat for Athens. Over a thousand Athenian citizens were killed. Sokrates, however, managed to save his own life and that of a young Alkibiades by remaining calm during the retreat and showing any pursuing enemy troops that he would fight them if they tried to have a go at him. Several ancient sources speak admiringly of his bravery during the rout. No doubt the gratitude and attentions of the fabulously wealthy Alkibiades did much to help Sokrates through these hard times. He served again during the campaign that ended in defeat at Amphipolis in 422 BC, though we do not know if he displayed similar heroics there.

Thanks to victories elsewhere, the Athenians were still able to make peace on quite favourable terms in 421 BC, and things seemed to be looking up for them. During the period 421-413 BC, life in Athens was basically going on as normal. Those who were not involved in the disastrous Sicilian Expedition (415-413 BC) would have been able to live their life more or less as they were used to. Plato was still a boy around this time; Sokrates no doubt lived off of the generosity of wealthy patrons, though he refused to be paid for his teachings like the sophists he despised.

413 BC, though, is when things got really bad. When Athens began to raid the Peloponnese again, Sparta went back to war. This time, however, instead of invading once a year and burning what they could, the Spartans decided to build a permanent fort at Dekeleia in Athenian territory, and ravage the Athenian countryside all through the year. This effectively meant that local food production was permanently lost and Athens was under siege. At the same time, the Spartans sent a fleet into the Aegean to encourage Athens' many subject states to revolt. This cut off most of Athens' income and threatened the food supply from the Black Sea. Athenian finances were stretched to the breaking point in their attempts to send out a fleet large enough to deal with the Spartan threat.

During this desperate time, Athens relied on the cavalry for its home defence; the rich men who could afford to fight on horseback rode out every day to attack Spartan ravagers, prevent slaves from deserting, and generally do what they could to keep the invading force in check. Plato, being a young member of a very wealthy family, may well have served in the cavalry at this time, as Xenophon (another pupil of Sokrates) very likely did.

The rich men of Athens increasingly felt that they were bearing the brunt of the war effort, both in terms of cost and harship. In 411 BC, they staged an oligarchic coup, and overthrew the democracy. The coup was short-lived, and democracy was soon restored, but the resentment of the rich kept on building through the final years of the war. The cost of the conflict kept on rising even as Athens seemed resurgent from 410-405 BC, winning several major victories and wiping out the entire Spartan fleet three times over.

Lasting Athenian confidence is revealed by the fact that they repeatedly challenged the Spartans in their territory to pitched battle on land - a challenge the Spartans twice denied. Sokrates would not have taken part in these actions, though. He had reached the age of 60 around 410 BC, and was no longer liable for military service. In 406 BC, he was chosen by lot to serve as a councillor in the Boulê, the government body in charge of everyday affairs.

The curtain finally fell for Athens at Aigospotamoi in 405 BC. Attacked by surprise, their entire fleet was destroyed. Their last hope went up in smoke; the grain supply from the Black Sea dried up; overcrowding and squalor increased at Athens as the Spartans tightened the noose and drove any Athenians living overseas back into their home city. Over the winter of 405-404 BC, the city was starved into submission. Plato's wealth would probably have kept him reasonably well fed, but Sokrates may have suffered, like many poorer citizens did. Athens surrendered in 404 BC and was forced to renounce its empire and tear down its walls.

The war was a demographic disaster for Athens. Scholars estimate that an adult male citizen population of 60,000 in 431 BC had fallen to a mere 25,000 by 403 BC. Due to the enemy presence at Dekeleia, the countryside lay in ruins. With the fall of the empire, state finances had collapsed. Of the once mighty Athenian fleet of over 300 triremes, the Spartans allowed them to keep just 12.

To add insult to injury, the Spartans abolished the democracy and put in place a narrow oligarchy known as the Thirty - or more ominously, the Thirty Tyrants. This puppet regime proceeded to unleash a reign of terror on what remained of Athens. Up to 1500 citizens are said to have "disappeared", their property confiscated to increase the holdings of the wealthy Thirty. Hundreds more were exiled. This dreadful regime was propped up by none other than the dissatisfied cavalry - the rich men who wanted power in return for shouldering the burdens of the war. Both Xenophon and Plato may have been involved in this. Luckily for them, once the democratic insurgency of Thrasyboulos gained momentum and the democracy was restored, Thrasyboulos ordered all past crimes to be forgotten, in a universally admired attempt to restore harmony to a war-torn, traumatised population.

Still, forgetting is more easily said than done. Part of the reason for Sokrates' trial and execution four years later was that he had long been critical of the democracy. Such dissenting views could no longer be tolerated in such a prominent figure.