Diogenes ( dy-OJ-in-eez; Ancient Greek: Διογένης, romanized: Diogénēs [di.oɡénɛ͜ɛs]), also known as Diogenes the Cynic (Διογένης ὁ Κυνικός, Diogénēs ho Kynikós), was a Greek philosopher and one of the founders of Cynic philosophy. He was born in Sinope, an Ionian colony on the Black Sea, in 412 or 404 BC and died at Corinth in 323 BC.Diogenes was a controversial figure. His father minted coins for a living, and Diogenes was banished from Sinope when he took to debasement of currency. After being exiled, he moved to Athens and criticized many cultural conventions of the city. He modelled himself on the example of Heracles, and believed that virtue was better revealed in action than in theory. He used his simple lifestyle and behaviour to criticize the social values and institutions of what he saw as a corrupt, confused society. He had a reputation for sleeping and eating wherever he chose in a highly non-traditional fashion, and took to toughening himself against nature. He declared himself a cosmopolitan and a citizen of the world rather than claiming allegiance to just one place. There are many tales about his dogging Antisthenes’ footsteps and becoming his “faithful hound”.
Diogenes made a virtue of poverty. He begged for a living and often slept in a large ceramic jar in the marketplace. He became notorious for his philosophical stunts, such as carrying a lamp during the day, claiming to be looking for an honest man. He criticized Plato, disputed his interpretation of Socrates, and sabotaged his lectures, sometimes distracting listeners by bringing food and eating during the discussions. Diogenes was also noted for having mocked Alexander the Great, both in public and to his face when he visited Corinth in 336 BC.Diogenes was captured by pirates and sold into slavery, eventually settling in Corinth. There he passed his philosophy of Cynicism to Crates, who taught it to Zeno of Citium, who fashioned it into the school of Stoicism, one of the most enduring schools of Greek philosophy. None of Diogenes’ writings has survived, but there are some details of his life from anecdotes (chreia), especially from Diogenes Laërtius’ book Lives and Opinions of Eminent Philosophers and some other sources.