Antisthenes was an ancient Greek philosopher and a pupil of Socrates, born in Athens around 445 BC. He is widely regarded as the founder of Cynic philosophy, which emphasized living a life of virtue in agreement with nature. Antisthenes taught that virtue, not pleasure, was the sole good and that it could be taught. His teachings greatly influenced later philosophers, most notably Diogenes of Sinope, who became the most famous of the Cynics.