470–399 BC
Socrates spent much of his adult life questioning prominent Athenians in public rather than pursuing wealth or office, a habit that made him enemies in a small city where reputational damage carried real consequences. Tried and executed in 399 BC on charges of impiety and corrupting the young, he left no writing of his own, so everything known about him comes through Plato, Xenophon and Aristophanes, sources that genuinely contradict each other in what scholars call the Socratic problem. Historians remain divided on whether his famous claim to know nothing was sincere humility or rhetorical strategy, whether he was religiously sincere, and whether his trial reflected genuine belief or a political pretext.