Diogenes of Sinope lived in Athens as a beggar, sleeping in a large clay jar and scorning wealth and convention. The story goes that he asked Alexander the Great only to step out of his sun. With provocative acts, he showed that happiness depends on very little and that many social rules are artificial.
Core ideas
Happiness lies in living with the minimum, in accordance with nature
Social conventions, wealth and fame are illusions that enslave
The sage is a citizen of the world and owes loyalty to no single city
The tradition: Cynic
Cynic comes from the Greek word for dog: the Cynics lived simply and without shame before convention. Diogenes is the most famous and radical representative of this school.