In Shakespeare’s play Hamlet, a ghost, taking the form of Hamlet’s recently deceased father, appears to Prince Hamlet one night. The ghost says that he was, in fact, murdered by his brother Claudius, who now (by virtue of having married Hamlet’s mother Gertrude) occupies the throne. The ghost exhorts Hamlet to take revenge on Claudius. When Hamlet sees the ghost, he is not sure if it is, in fact, his father’s spirit or a demon whose aim is to deceive him. Julius Caesar’s ghost appears to Brutus in Shakespeare’s Julius Caesar to warn Brutus of his impending defeat.