The Black Death or Bubonic Plague swept through England and Europe from 1347 to 1350. By the time it was finished one third of Europe's population was dead, 25 million people. It was one of the worst disasters in human history.

Let's take a step or two back. At this time in history witches were viewed with suspicion and fear. The cat was considered to be the witches "familiar", the witches companion, and the disciple of the devil. Accordingly during this period cats also viewed with suspicion and killed. By the late 1300's the cat was almost extinct in Europe.

Cat's through out the ages have proved very efficient in rodent control in farm and domestic environments and so with the extinction of the cat the rodent population in Europe flourished. The rat carried, you guessed it, the bacteria for the Black Death in its blood. On its journey it had a companion, the Oriental Rat Flea (Xenopsylla cheopis) which drank infected blood from the rat. Transferring to a human host the flea regurgitated bacteria that had been developing in its gut into its new human host when it bit them.

Through fear, and subsequent elimination, of the Witches Familiar the people of Europe indirectly created the ideal environment for the spread of the Black Death and nearly caused their own demise.