The M'Naghten Rules originate from a famous English case in 1843 and provide the foundational test for the defence of insanity in common law jurisdictions. These rules state that an accused can be acquitted on the grounds of insanity if it is proved that, at the time of the act, they were suffering from a "defect of reason, from disease of the mind," which made them incapable of knowing the "nature and quality of the act" or, if they did know it, that they "did not know he was doing what was wrong." These principles are codified in Section 84 of the Indian Penal Code.