2. Pope Gregory IX ordered the extermination of black cats
Another widely reported piece of strange history is that Pope Gregory IX issued a papal decree which ordered black cats, which were symbols of Satan, be exterminated. Some versions of the story report that the order extended to all cats, and as a result of the consequent removal of cats in Europe, rodent infestation led to the rapid spread of the black plague. Gregory did issue a papal bull around the same time that he created the Papal Inquisition in 1233. This was directed towards the heretical practices in Germany he called Luciferian. He issued the bull to the Church and Civil authorities, directing them to stop the practice by destroying the heretics.
Part of the ritual of the Luciferians were reported to Gregory by Konrad von Marburg. (It was also uncovered through confessions under torture.) The ritual included the statue of a black cat, which would come to life as the ritual came to an end. The heretics taking part in the ritual were hunted down and dealt with appropriately. Some local authorities undoubtedly took it upon themselves to kill black cats as part of the crackdown, and they have always been associated with bad luck and witchcraft, but the papal bull, called Vox in Rama did not order the extermination of cats in Europe of any color.