In 399 BC, Socrates was put on trial in Athens. He was seventy years old. The charges: impiety (not believing in the gods of the city) and corrupting the youth.
The trial was political. Everyone knew it. Socrates had made enemies over decades of questioning powerful men in public. But the specific timing — just five years after Athens' defeat in the Peloponnesian War — was crucial.
Athens after the war
Athens had lost the war to Sparta in 404 BC. The city's walls were torn down. Its fleet was destroyed. Sparta imposed a brutal oligarchy — the Thirty Tyrants — who ruled through terror for eight months.
When democracy was restored in 403 BC, there was an official amnesty. The past was supposed to be forgotten. But resentment lingered. Many blamed intellectuals and philosophers for weakening traditional values. Socrates, the most famous questioner of all, became a scapegoat.
Worse, one of the Thirty Tyrants had been Critias — a former associate of Socrates. Another was Plato's relative Charmides. Socrates had never supported the oligarchy, but the association was enough to make him suspect.
The charges
Three men brought the formal accusation: Meletus (a poet), Anytus (a politician), and Lycon (a rhetorician). The indictment read:
The real reasons were different. Socrates questioned everything — including democracy itself. He had criticized the Assembly's decisions. He had exposed the ignorance of politicians and generals. He had made powerful people look foolish in front of their sons.
Most dangerously, he had taught young aristocrats like Plato to question authority. In a democracy still traumatized by civil war, this felt like subversion.
The defense
Plato was present at the trial. He heard Socrates defend himself — or rather, refuse to defend himself in the conventional way.
Socrates did not plead for mercy. He did not appeal to emotion. Instead, he turned his defense into a philosophical argument. He claimed that his questioning was a service to Athens — like a gadfly stinging a noble horse awake. If they killed him, Athens would fall back into complacency.
He told the jury that he would never stop philosophizing, even if they acquitted him on condition that he remain silent. "The unexamined life," he said, "is not worth living."
This was not the speech of a man trying to win an acquittal. It was the speech of a man insisting on his principles, even at the cost of his life.
The verdict
The jury — 501 Athenian citizens — voted. Socrates was found guilty: 280 to 221. It was a narrow verdict. If just 30 more jurors had voted differently, he would have been acquitted.
Under Athenian law, both the prosecution and the defense could propose a penalty. The prosecution demanded death. Socrates, instead of proposing exile or a fine, suggested that Athens should reward him with free meals in the Prytaneum — the highest civic honor.
The jury, insulted by what seemed like arrogance, voted again. This time the margin was wider: death. Socrates would be executed by drinking hemlock.
The final days
Execution was delayed because a sacred ship had been sent to Delos. No one could be put to death until it returned. Socrates spent about a month in prison, continuing to converse with his followers.
In the Crito, Plato describes how friends offered to help Socrates escape. He refused. To break the law — even an unjust law — would be to contradict everything he had taught. He would not betray his principles to save his life.
On the final day, described in the Phaedo, Socrates spent his last hours discussing the immortality of the soul. He was calm, almost cheerful. When the time came, he drank the hemlock without hesitation.
Plato was not there. The Phaedo notes: "Plato, I think, was ill." Whether this was literally true or whether Plato could not bear to witness the execution, we don't know.
The impact on Plato
Socrates' death was the defining event of Plato's life. It shattered his faith in Athenian democracy. How could a system that claimed to embody justice execute the wisest and most just man in the city?
This question would drive everything Plato wrote. The Republic is, in part, an attempt to imagine a city that would never kill Socrates. The Theory of Forms is, in part, a reaction: if political life is this corrupt and unstable, then truth must exist somewhere beyond it — in an eternal, unchanging realm.
Plato's entire philosophical project can be understood as an effort to vindicate Socrates and prevent such an injustice from ever happening again. He would spend the rest of his life trying to answer the questions Socrates raised and building institutions — like the Academy — that would keep the Socratic method alive.