Black cats are considered to bring bad luck to humans, as they have long been conceived of as the embodiment of demons and witches.
Thousands of years ago, cats of all colors enjoyed a good life in ancient Egypt. Then the person who kills a cat was immediately executed, according to How Stuff Works.
Several millennia later, Christianity spread across Europe undermining the customs and traditions of local pagans. This meant that pagan symbols were slandered, like the Roman goddess Riana. Cats have also become a pagan symbol due to a connection with gods and goddesses.
In 1233, Pope Gregory IX nailed the last nail to the coffin of a black cat when he declared the black cat the incarnation of the devil. With this statement, Christians found black cats and burned them alive at festivals to punish the incarnation of the devil. The situation was so serious that in the 14th century cats were almost extinct in parts of Europe.
Over the following centuries, superstitious people believed that black cats were caused by disguised witches. Others claim that black cats can actually turn into witches after being a member of the wizarding world for 7 years. In the 16th and 17th centuries, anyone who owned a black cat was considered a witch and sentenced to death.
The black cat superstition persists to this day, although there really is no scientific connection between a black cat and its bad luck.
