Sleep (Greek hýpnos, Latin somnus), the opposite of being awake, is a necessarily recurring state; in antiquity it was already thought of as the brother of death and a bridge to dreaming (Dream), but the phenomenon was also approached with scientific interest: Aristotle described sleep as a physiological process which, together with digestion, enables the revival of bodily functions and cognition. In the medicine of the Middle Ages and Renaissance, Aristotle’s theory was recognized, but the humoralism and dietetics of Hippocrates and Galen were more influential. …