"Hamlet, Prince of Denmark" by William Shakespeare is a tragedy. Set in Denmark, the play depicts Prince Hamlet and his attempts to exact revenge against his uncle, Claudius, who has murdered Hamlet's father in order to seize his throne and marry Hamlet's mother. On a cold night on the ramparts of Elsinore, the Danish royal castle, the sentries Bernardo and Marcellus discuss a ghost resembling the late King Hamlet which they have recently seen, and bring Prince Hamlet's friend Horatio as a witness. After the ghost appears again, the three vow to tell Prince Hamlet what they have witnessed.