The climax of the play is set in the court of the Duke of Venice. Shylock refuses Bassanio's offer of 6,000 ducats, twice the amount of the loan. He demands his pound of flesh from Antonio. The Duke, wishing to save Antonio but unable to nullify a contract, refers the case to a visitor. He identifies himself as Balthazar, a young male "doctor of the law", bearing a letter of recommendation to the Duke from the learned lawyer Bellario. The doctor is Portia in disguise, and the law clerk who accompanies her is Nerissa, also disguised as a man. As Balthazar, Portia in a famous speech repeatedly asks Shylock to show mercy, advising him that mercy "is twice blest: It blesseth him that gives and him that takes" (Act IV, Sc 1, Line 185). However, Shylock adamantly refuses any compensations and insists on the pound of flesh.