Familiars?

(I Know Witches Do Not Worship The Devil. I Practice Witchcraft)

I was watching a documentary on the Salem Witch Trials, and they were saying something about "The Witches Teat." Which is some sort of mole or mark that the devil puts on a witch so that she can feed her familiar.
I know this is all a load of crap. But it made me think; did Christianity create much of the modern themes of Witchcraft? Or did the concept of familiars exist before the Burning Times?
And I know this would be almost impossible to figure out because the only people who knew how to read or write were either rich or priests.
I would really like to know. And does anyone else have any sort of witch concept that may have been created by Christians?
Just curious. :)
Blessed Be!