How do we know werewolves are real?

Those of you who said werewolves are not real, you are wrong. If they aren't real, were did the tale come from? There had to be a time when werewolves were known of. The reason of it is because if they weren't real, why, or rather how, would someone make up such a creature with such a rich history? It makes sense to see werewolves as real, they had to be. Where would the person get the tale from. At the origin, it had to of been from something, someone, somewhere real were the wolfman exsisted.