In 1233, Pope Gregory IX issued a papal bull declaring that black cats were agents of Satan — triggering one of history's strangest church-sponsored moral panics.
In June 1233, Pope Gregory IX issued a papal decretal called Vox in Rama, aimed at condemning a German heretical sect called the Luciferians. The document described their alleged initiation rituals in vivid, bizarre detail — and put cats at the center of them.
According to the bull, initiates would be greeted by a black cat that came to life and walked backwards. New members were required to kiss the cat beneath its tail. The document went on to describe further rituals involving a pale, emaciated man and the desecration of the Eucharist. Whether any of this was real or entirely fabricated by inquisitors is unknown.
The document was distributed to Emperor Frederick II, the Archbishop of Mainz, and the notorious inquisitor Konrad von Marburg, who used it to authorize a campaign against alleged heretics in Germany. Konrad's crusade became so extreme — executing people on little evidence — that he was eventually assassinated by a group of German nobles.
A popular modern claim holds that Vox in Rama triggered a Europe-wide campaign to exterminate cats, which then caused rat populations to explode and worsened the Black Death of the 14th century. This story has been repeated widely but historians largely dispute it — the document doesn't actually order cat-killing, and archaeological evidence doesn't support mass cat persecution.
What is clear is that medieval Europe had a growing cultural association between cats — especially black ones — and witchcraft and devil worship. Vox in Rama helped crystallize and officially sanctify that association, giving it the weight of papal authority.
The real legacy of Vox in Rama is less dramatic but still significant: it's one of the earliest official church documents connecting cats with Satanism, feeding a superstition that would persist for centuries and make life difficult for cats — and the women accused of keeping them as 'familiars' — throughout the witch trial era.