The Cat in Gregory IX’s Heresy Case
In 1233, Pope Gregory IX issued a decree known as Vox in Rama, describing alleged rituals practiced by a German heretical group. In one lurid passage, an initiate supposedly encountered a black cat, which was treated as a manifestation of the devil. The account helped associate cats—especially black cats—with heresy and evil in later retellings.
But Gregory did not issue a general order to kill cats. The decree targeted a particular alleged heresy, and its cat episode was part of a description of supposed occult rites, not a ruling that cats as a species were demonic.
Why the Plague Story Doesn’t Follow
The claim that this decree caused a continent-wide cat slaughter, which then allowed plague-carrying rats to multiply, is a popular but poorly supported chain of events. There is no clear evidence that Vox in Rama led to widespread killing of cats across Europe. Nor can the plague’s devastating spread in the 14th century be traced to this single decree.
The real historical consequence is narrower: the document shows how religious authorities could use vivid accusations of devil worship to mark groups as dangerous. Its memorable black-cat episode later became attached to a much larger story about superstition and plague—but the surviving evidence does not support the claim that Gregory IX’s decree caused a massive spike in plague deaths.
