witch or not

   Back in the mid evel days their where many superstitions but the most comen  superstition was the witch ,they where laws against black magic which most associated with a witch there were cases wear people burned people if they were accused with being a witch and with their powers killed someone. I'm not actually surprised that they thought that witches were real,they dint know much about many diseases or how to cure them so they probably just really thought it was black magic.My question is why did they burn the people and were they even 100% they were a ?omg witch craft