In William Shakespeare's tragedy Hamlet, the title character learns from the ghost of his father that his father was murdered by his brother, Hamlet's uncle Claudius. Hamlet wants Claudius to be revealed as his father's murderer, but doing this Claudius will be difficult. Also, Hamlet needs to prevent Claudius from feeling like he is a threat to him. After all, Claudius might suspect that Hamlet would want to avenge his father's death. Accordingly, to prevent himself from appearing to be a threat and to gain access to Claudius at the same time, Hamlet decides that he will pretend to be insane ("How strange or odd soe'er I bear myself"; "To put an antic disposition on").
In his feigned madness, Hamlet convinces Ophelia and her father Polonius that his madness is caused by his love for Ophelia. Unfortunately, Hamlet's plan does not work out the way he hoped because he accidentally kills Ophelia's father, whom he mistook for an eavesdropping Claudius.