De Agricultura

Therefore the Olympian contest is the only one that justly deserves to be called sacred; meaning by this, not that which the inhabitants of Elis celebrate, but that which is instituted for the acquisition of the divine, and Olympian, and genuine virtues. Now, as competitors in this contest, all those have their names inscribed who are very weak in their bodies, but very vigorous in their souls; and then, having stripped off their clothes, and smeared themselves in the dust, they do all those actions which belong to skill and to power, omitting nothing which may conduce to their gaining the victory.