A miller is a person who operates a mill, which is a machine used to grind grain (such as corn or wheat) into flour. Milling is one of the oldest human occupations, and millers were important to the development of agriculture. The materials ground by millers are often foodstuffs, and the physical grinding of the food allows for easier digestion of its nutrients and saves wear on the teeth. Non-food substances needed in a fine, powdered form, such as building materials, may also be processed by a miller. In a traditional rural society, a miller is often wealthier than ordinary peasants, which can lead to jealousy. Millers are often accused of associating with thieves and were targeted in bread riots during times of famine. Conversely, millers might be in a stronger position vis-a-vis feudal landowners than are ordinary peasants.