In medieval Europe, cats were believed to be witches' familiars, and black cats were especially feared as bad omens. Whenever there was a crop failure or disaster, people would blame the cats. As a result, innocent cats were put on trial and lost their lives. However, the behavior caused by superstition and prejudice brought a great price to the village. Rats increased rapidly, crops were destroyed, and diseases spread. The actions of those who chased away the cats ultimately disrupted the village's ecosystem.