Superstitions allotted the black death to the Devil.The Black Death, also known as the Black Plague, was apparently caused by the Devil himself, at least that is what superstitious people of the Dark Ages thought. This term refers to a series of pandemic diseases decimated almost 200 million people in Europe and Asia from 1347 to 1351. It turned out that the actual actual cause of the plague wasn't Satan, like many believed, but rather the lack of hygiene, helped by the outbreak of Yersinia pestis, bacteria carried by rats.