William Shakespeare's Famous Quote

"Not a Mouse Stirring"

What does this quote mean?

In William Shakespeare's Hamlet, at the beginning of the play, Francisco and Bernardo are on guard duty on the platform of the castle at Elsinore, Denmark. The night has been very quiet. Bernardo asks Francisco about how the night is going. Bernardo asks, "Have you had quiet guard?"(1.1.11). Francisco replies in a sarcastic tone, "Not a mouse stirring" (1.1.12). The extreme stillness and silence of the night are captured in the quote which sets up the striking contrast that is about to occur when the ghost appears . This quote adds a dimension to the tone making everything seem real and typical.