"Know thyself"

A Greek philosophical maxim inscribed upon the Temple of Apollo in the ancient Greek precinct of Delphi. The best-known of the Delphic maxims, it has been quoted, analyzed by applied in many ways. Although traditionally attributed to the Seven Sages of Greece, or to the god Apollo himself, the inscription likely had its origin in a popular proverb. The principal meaning of the phrase in its original application was "know your limits" – either in the sense of knowing the extent of one's abilities, knowing one's place in the social scale, or knowing oneself to be mortal. In the 4th century BC, however, the maxim was drastically re-interpreted by Plato, who understood it to mean, broadly speaking, "know your soul".