The Black Death of 1347-1352 CE is the most infamous plague outbreak of the medieval world, unprecedented and unequaled until the 1918-1919 CE flu pandemic in the modern age. The cause of the plague was unknown and, in accordance with the general understanding of the Middle Ages, was attributed to supernatural forces and, primarily, the will or wrath of God.
This is a companion discussion topic for the original content at https://www.worldhistory.org/article/1541/religious-responses-to-the-black-death/.