Antisthenes was a Greek philosopher who lived from around 445 to 365 BCE. He was a student of Socrates and is best known for founding the philosophical school of Cynicism. Antisthenes emphasized the importance of virtue and self-sufficiency, advocating for a simple life in accordance with nature. His teachings challenged societal norms and materialism, promoting the idea that true happiness comes from living a life of virtue rather than pursuing wealth or pleasure. Antisthenes' ideas influenced later philosophers, including Diogenes of Sinope, who is often associated with the Cynic movement.