How would sixteenth-century audiences react to the witches in Macbeth?

First, we should recognize that Macbeth was not performed until the seventeenth century. Shakespeare composed the work at around the turn of the century. Still, witch hunts were not uncommon at all, especially on the European continent, and there is no doubt that many Europeans still believed in them. England and Scotland (the setting of Macbeth) witnessed a number of witch hunts in the seventeenth century, and of course the Salem trials, which rank among the most famous witch hunts in history, occurred more than eighty years after Macbeth was first performed. So it is important to note that many of Shakespeare's audience would have believed that witches were a reality, not a fantasy conjured up for dramatic purposes. Even some who did not literally believe in witches would have identified with one of the play's central themes: the role played by supernatural forces in the lives of human beings. Sometimes, as the witches in Macbeth demonstrate, these forces could be up to no good. On the other hand, it is worth noting that it is Macbeth himself that takes the actions that lead to his downfall--the witches do not themselves indulge in bloodshed. So Macbeth might have been viewed as a meditation on the interaction between malevolent supernatural forces and the all-too-human characteristics of self-destructive ambition and lust for power.