New light shed on Shakespeare's Macbeth

Contemporary optical science could have inspired a famous supernatural event in one of Shakespeare's darkest works, new research suggests.

And the bard may have used the emerging tricks with mirrors as special effects when the play hit the stage.

Did Elizabethan theater employ advanced optics? John Dee says maybe...

It's hard to tell from the article, but they seem to be implying that they were using an effect similar to Pepper's Ghost, although that seems unlikely. Perhaps it was some sort of magic lantern, first described in 1671 - 55 years after the Bard's death.