There are probably three reasons why cats were hated in mediaeval Europe, (1) it was an era when religion played a prominent role in people’s lives and if you were an atheist you were an outsider and classified as a witch “witchery was atheism and atheism was the biggest crime and sin”1 and also “witchery universally did not exist, but had an anti-Christian character, and included rejecting baptism and apostasy.”2 (2) all domestic cats were free-roaming and seen as highly independent and therefore outsiders. Perhaps this is the first instance of the domestic cat’s independence working against it and (3) a series of popes in the Middle Ages initiated the feline Holocaust in Europe which continued throughout the era.
I’m not going to expand on the first two items but the third needs some discussion.
Roman Catholicism – the Popes
Pope Gregory IX (1147-1241). As mentioned, this Pope initiated what has been described as the feline Holocaust3 in Europe. In a papal bull of 1233 he denounced the black cat as diabolical. He therefore gave his official blessing to the widespread persecution of cats across Europe. It was the beginning of five centuries of cat-hating torture and burning and the association of cats with witchcraft. This pope must have hated cats; an ignorant hatred.
The revered cat of ancient Egypt had become the sorcerer’s cat of Mediaeval Europe. The cat became linked in popular culture with witchcraft and black magic. The last execution of a cat for witchcraft in England was in 1712, well beyond the era of the Middle Ages.
The legacy subsists today in countries such as Africa. Hundreds of local cats were burnt in the city of Metz in north-east France in the ceremony of Cat Wednesday which took place on the second Wednesday in Lent. They were regarded as witches in disguise. In the 16th and 17th centuries 100,000 witches were executed in Germany, 75,000 in France and 30,000 in Britain when wherever possible cats were destroyed with them. Clearly many hundreds of thousands of domestic cats were slaughtered during this period.
Pope Innocent VII (1336-1415) stepped up the onslaught against the domestic cat resulting in millions more feline deaths when he added his voice to the persecution of cats.
Pope Innocent VIII (1432-1492). This Pope in his papal bull of 1484 condemned witchcraft. He ordered inquisitors to try witches and destroy them. In particular he made the point that witches’ cats were to be burned with them. We are told that two Dominican Friars from Germany whose names are Kraemer and Sprenger, persuaded him to issue his papal bull. This triumvirate of cat haters were probably the worst in the history of the domestic cat.
Set against a background of the dominance of religion during mediaeval times and atheism as akin to witchcraft together with the resolute independence of the domestic cat, the cat became associated with witches which led to their heavy persecution. Cats were likened to witches and the devil incarnate. Behind it all is religion. Christianity has a brutal history of heavy intolerance and ghastly superstition supported by violence.
These are simply my thoughts. There are many ways to answer the question in the title. I don’t claim that what I written is an absolute answer to why cats were hated in Mediaeval times. It is a personal overview. There is though as mentioned one irrevocable truth: religion, specifically Christianity, is at its core. Cats are hardly mentioned in the bible.
References: (1) 16th century jurist Jean Bodin (2) English cleric and Cambridge theologian William Perkins (3) Dr Desmond Morris (4) Michael Broad.