"There's more than one way to skin a cat" <- Where did this sick expression come from?

Did people actually skin cats at some point? If so, why? To make fur? Did they knock the cats out at least before they skinned them or did they skin them alive? What's up with all this barbaric animal cruelty all over the world? It's so prevalent that we even have it embedded in our idiomatic expressions. Sick and wrong if you ask me.