Diogenes of Sinope, a provocative thinker from ancient Greece, challenged the norms of his time with his radical philosophy and unconventional lifestyle. As a founding figure of the Cynic school, Diogenes lived in accordance with his principles of self-sufficiency and moral integrity, eschewing material possessions and societal conventions. His infamous encounters with Plato and Alexander the Great showcased his fearless commitment to truth and virtue, inspiring generations of philosophers to question authority and live with authenticity.