Antisthenes (Ἀντισθένης; c. 446 – c. 366 BC) was a Greek philosopher and a pupil of Socrates. He adopted and developed the ethical side of Socrates' teachings, advocating an ascetic life lived in accordance with virtue. Later writers regarded Antisthenes as the founder of Cynicism philosophy. Filled with enthusiasm for the Socratic idea of virtue, Antisthenes founded a school of his own in the Cynosarges

Diogenes (Διογένης), also known as Diogenes of Sinope, was a Greek philosopher and one of the founders of Cynic philosophy. 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.

Crates (c. 365 – c. 285 BC) of Thebes was a Greek Cynic philosopher, the principal pupil of Diogenes of Sinope and the husband of Hipparchia of Maroneia who lived in the same manner as him. Crates gave away his money to live a life of poverty on the streets of Athens. Crates lived a life of cheerful simplicity. He was nicknamed the Door-Opener