9. Plato and the atheists Athens in 399 BC was a fearsome place to be. In 404 the city had fallen to the Spartans, after 27 bruising years of warfare, sometimes bloody and sometimes attritional. The aftermath was horrific. For thirteen months, the democracy was suspended, and a pro-Spartan oligarchy known as the ''thirty tyrants'' was installed. Their leaders, Theramenes and Critias (possibly the author of the atheistic ''Sisyphus fragment''), were famed for their brutality. A faction loyal to the old democracy was identified, arrested and executed. After a while, a power struggle between Critias and Theramenes saw the latter hauled off and killed.

In 403, their rule ended when rebellious forces led by the staunch democrat Thrasybulus joined battle near the Piraeus. After more fighting, the democracy was restored. Despite an amnesty forbidding mnÄ"sikakia , ''the remembering of wrongdoing'', Athens in 399 was scarred and haunted by recent events. This was the backdrop for one of the most important events in Greek cultural and religious history, the trial and execution of Socrates. Socrates, Athens'' most famous philosopher, had found himself reluctantly embroiled in the events of the previous five years. Critias had been one of his students, along with another of the tyrants, Charmides. Both of these were relatives of Plato, Socrates'' star student and later apologist; in fact, two of Plato''s dialogues featuring Socrates are called Critias and Charmides . Certainly Socrates'' relationship to the junta was not unambiguous.

He had been mandated, along with others, to arrest one Leon of Salamis; he had refused, however because (according to Plato) he feared committing injustice more than the recriminations that would follow. On that occasion, he was saved by the fall of the tyrants from any repercussions from his principled insubordination. But the stain of association with that hated band, which the Athenians of the newly restored democracy were keen to drive from their memory, was hard to shift. The idea that his association with the tyrants was behind Socrates'' execution stuck around for a long time. But association with the tyrants was not the explicit basis of the charge against Socrates, which ran: ''Socrates commits a crime in not recognising the gods the state recognises, and introducing other, new divine powers instead. He also commits a crime by corrupting the young''. Diopeithes'' decree providing for the impeachment of ''those who do not recognise the gods'' lies in the background for the accusation: the shared language of ''not recognising'' ( mÄ" nomizein ) suggests this much. The vaguer charge of asebeia , ''impiety'', was also hanging in the air.

But as so often in Athenian criminal prosecution, impressionistic as it was, not everything corresponds exactly to known legislation. ''Corrupting the young'' was not a crime on the statute book. The additional accusation was no doubt designed to influence the jurors with insinuations: this, after all, was the philosopher who had taught Critias and Charmides (and Alcibiades too) when they were young men. There was also a pederastic hint in the word ''corrupt'': Socrates was well known for his attachment to handsome youths. For an older man to court a younger boy was not in any sense seen as a moral offence, but it was a practice associated with the aristocratic elite, and so likely to play badly with the largely working-class jurors. Whatever the underlying political motivations, the explicit force of the charge lay in the assertion that he had turned his back on the religion of the city, and invented his own private mysticism. This accusation was rooted in a peculiar foible of Socrates'': he claimed to have access to a daimonion , a ''divine thing'', which he identified sometimes as a voice in his head and sometimes as a ''sign from the god''. He was claiming a direct communion with an unspecified deity, a form of divine engagement that in one sense cut right across the usual ideology of Greek religion, which insisted that collective ritual marked one''s subservience to the social order.

Believing that gods speak to us was not in itself so very strange: Greeks imagined that gods revealed all sorts of things through dreams, signs, and even direct manifestations (''epiphanies''). It was the idea of an enduring one-to-one relationship with his own personal deity that was the problem. If Socrates believed that he alone had been granted access to the full depths of the divine, while conventional religion merely paddled in the shallows, that would have been deeply threatening to the civic consensus. Earlier philosophers had claimed similar things: the Presocratic philosopher Parmenides of Elea, for example, describes a journey on a chariot, through a locked gate, to the temple of a goddess who reveals to him the ways of truth and hollow belief. But Parmenides was not unfortunate enough to have to defend this claim in the aftermath of a bloody aristocratic regime spearheaded by some of his followers. Socrates'' (alleged) claim to exclusive access to divine truth could have been presented to his democratically-minded peers as a dangerous attempt to legitimate the rule of the many by the elite. What did Socrates really think about the gods? Did he really ''not recognise the gods of the city'', as the accusation ran? Did he believe firmly in the ''divine thing'', or was that simply a whim of this famously ironic philosopher? How did he square this emphasis on divine revelation with his philosophical commitment to rationalism? Barring some remarkable discovery, these questions will never be answered conclusively, for Socrates - like Jesus and Mohammed (and, indeed, several other noted Greek philosophers - wrote nothing down. Every single piece of evidence for him comes mediated through others.

What is more, apart from the scurrilous portrait painted by the comic poet Aristophanes in 423 BC (in Clouds ), during his lifetime, every major piece of evidence is carefully polished up by one of his loyal supporters, in the aftermath of the trial. Socrates is a paradox: we know all about his central importance to Athenian cultural life in the late fifth century, but there is little certainty about his beliefs. The two most important of these sources for Socrates'' thought are also the two most vigorous polishers of the Socrates myth: Xenophon and Plato. Xenophon (approximately 430-355 BC) was an aristocratic Athenian who combined a diverse literary output with a colourful military life. An associate of Socrates in his youth, he left Athens in the turbulent years after the end of the Thirty Tyrants to join the Greek mercenary force supporting the failed attempt of the Persian Cyrus the Younger to oust his brother, Artaxerxes II, from the throne. His epic march from Mesopotamia to the Black Sea (where the soldiers uttered the famous cry ''The sea! The sea!''), and thence to Greece, is recorded in his Anabasis . When he returned, he began associating with his native city''s other nemesis, Sparta, and even fought with the Spartan king Agesilaus II against Athens in 394. This loyalty to Sparta won him a beautiful country house at Scillus, near Olympia (site of the games); there he wrote many of his literary works, including a biography of Agesilaus, an idealised novel on the subject of Cyrus I of Persia (the sixth-century creator of the Persian Empire), and four works on Socrates: a fictionalised version of his defence speech at the trial, a collection of conversational pieces, a dialogue on household management and a description of a symposium.

Although he may have returned home in his declining years, it is fair to say that Xenophon was far from a conventional Athenian. Whether he had become alienated by the horrors of the Thirty Tyrants and the aftermath (for which his History of Greece is the primary source), or whether he was simply perverse by inclination, he seems to have allied himself with persons most unwelcome to Athenian ideology: Persian kings, Spartan kings, and Socrates. Plato (approximately 424-347 BC), the most famous of all philosophers, was another native Athenian aristocrat, and an almost exact contemporary of Xenophon''s; but whereas Xenophon''s life was characterised by experimentation and adventure, Plato spent most of his adulthood beavering away at his writing (37 works are transmitted under his name, at least 26 of which are genuine). His one big foray into Realpolitik may have been a trip to the court of Dionysius II of Sicily (ruled 367-357 and 346-344). According to a surviving letter that purports to be written by Plato himself, he was invited over to Sicily on two occasions, first by Dionysius'' father (during his own reign) and second (early in the new king''s reign) by his philosophically inclined uncle, Dio. On both occasions, the plan was to curb the young man''s lavish appetites, and to put into practice the Platonic ideal of the ''philosopher-king''. Dionysius, however, was congenitally indulgent and cruel. Dio was exiled, only to return with an army and depose Dionysius.

Whether Plato''s Sicilian sojourn really took place all depends on the question of the authenticity of the letter. In any case, Plato developed a reputation throughout later antiquity as a head-in-the-clouds idealist, as other-worldly as his mentor Socrates himself; and the Sicily story came to be seen as a sign of his inability to translate his ideals into practice. Lucian, the playful satirist of the second century AD, wrote a fantasy story ironically titled The True Stories . In it he visits the underworld, where he meets all of the famous figures of the past, except for Plato ''it was said that he was living in his imaginary city in the republic and under the laws that he himself had composed''. T.