Montaigne 1.44
What, then, is sleep? And what, if any, are its virtues? A sound sleep the sign of both exhaustion and courage.
The knowledge we have of this mans unmated-haughty heart by the rest of his life, may make us judge with all securitie that it only proceeded from a spirit so far elevated above such accidents that he dained not so much as to trouble his minde with them no more than with ordinarie chances (trans. Florio).