Why did shakespeare put the witches in macbeth?

Question

I'm looking at what role they play in Macbeth, aside from their necessity in suggesting to macbeth about him becoming king, i mean how did it appeal to the audience?

I've thought about things like witches were the 'baddies' of the time, and entertainment - witch hunt...

but I'm having some trouble getting my head around it all,

Thanks for any help!

Answer 1

They are not just "baddies". They symbolize the dark parts of Macbeth's soul. They're the ones that instill him with the illusion of grandeur and invulnerability, and the paranoia that lead to his downfall.

Answer 2

this might help  http://www.slashdoc.com/documents/75894