In superstition, folklore and fairy tales, what is a “familiar”?

“Familiars”(or spirit guides) were originally seen as a form of guardian angel. In ancient Rome, spirits were thought to protect households. In ancient Greece, some believed in a personal spirit that guided a person’s actions. Socrates talked about having one.

In 1604, a Witchcraft Act was introduced in England which made working with (evil) spirits a capital offence. The act also referenced “familiars”, believed to be witches’ demonic companions. In the witch hunts of the 17th century, these “familiars”, often called ‘imps', were thought to exist as small animals and a witch’s power could affect another person through the “familiar”. References to such “imps” appear in some court records as late as the early 20th century.

“Familiars” were believed to teach witches how to do magic and that witches used them as spies thanks to their shape-shifting abilities. Cats, dogs, owls, toads, and mice were all viewed as possible animal forms of "familiars". During the medieval period, “familiars” weren’t physical animals, but rather spirits that took the form of these animals. ‘Evil’ witches used demons as “familiars” to cause harm. ‘Good’ witches might use fairies, or even angels, as “familiars” to heal.