Exercise has its origins in medieval torture. Originally people just thought that it was food deprivation and sleep restrictions that caused prisoners to look so emaciated. Eventually, however, they discovered that it was the actual act of torture that caused people to lose weight and look more fit. Furthermore, it was found that the more intimidating the torture device looked, the more pronounced the fitness results.
This knowledge was very nearly lost to the ages with the arrival of the Renaissance were it not for a few enterprising dungeon keepers who began selling “lightly used” torture devices as exercise equipment. The rest, as they say, is history.