Self-control is the chief element in self-respect, and self-respect is the chief element in courage.

“Self-control is the chief element in self-respect, and self-respect is the chief element in courage. [...] For the whole earth is the tomb of famous men; not only are they commemorated by columns and inscriptions in their own country, but in foreign lands there dwells also an unwritten memorial of them, graven not on stone but in the hearts of men. Make them your examples, and, esteeming courage to be freedom and freedom to be happiness, do not weigh too nicely the perils of war."

-- Thucydides, The History of the Peloponnesian War, 400BC