Ethical theory in Greek culture predates philosophical reflection. The main ethical category for ancient Greeks was arete or virtue, which meant a certain strength or ability, or even force. The objective of a successful life was attaining doxa, or glory. Also an important concept in Greek culture was that of hybris, trying to go beyond one's possibilities. The literary source of this folk ethical theory can be seen in Homer, Greek tragedy and also Aesop's fables.
The first philosophers, the Presocratics, occasionally reflected on ethics. Heraclitus thought that injustice appears only in the eyes of men, and that a divine perspective would show that everything is just. Pythagoras founded a sect in which a good reincarnation (metempsychosis) was to be attained through following certain ascetic practices. Democritus proposed cheerfulness as the supreme goal of life.
An important change came with the Sophist movement, who resembled professional teachers. They traveled from one city to another, and were concerned with ethical problems. Protagoras was a sophist and the first formulator of relativism in Western thought. By saying man is the measure of all things, he attacked the unchallenged notion of a fixed reality.
Socrates was a milestone in the history of ethics. He regarded for the first time areté as the rational part of the human soul/mind (psyché).