In the most high and palmy state of Rome,
A little ere the mightiest Julius fell,
The graves stood tenantless, and the sheeted dead
Did squeak and gibber in the Roman streets.

– William Shakespeare

Hamlet, Act 1, Scene 1. Horatio says this to the castle guards after the sighting of the Ghost. Emphasizing the seriousness of the event, he recalls that before the mighty Julius Caesar was assassinated the dead rose from their graves and ran squeaking through the streets of Rome. This foreshadows the revenge that Hamlet will embark upon, leading to the death of his uncle, mother and himself.