King Lear — Act 3, Scene 5: Gloucester's castle.

Cornwall enters with Edmund and says he intends to punish Gloucester before leaving. Edmund acts worried that his loyalty may be doubted, while Cornwall reads Gloucester’s hidden letter and decides Edgar’s supposed rebellion is serious. He accepts Edmund’s claim that Edgar is guilty and tells him the paper has won him Gloucester’s earldom. Cornwall then sends Edmund to find Gloucester so he can be arrested. Alone in an aside, Edmund admits that if he discovers his father aiding Lear, it will strengthen Cornwall’s suspicion, but he still keeps up the appearance of loyalty. Cornwall promises to trust him and treat him like a favored son.