In criminal trials, the insanity defense is the claim that the defendant is not responsible for his or her actions due to a mental illness. People who have been determined to be insane have been exempt from full criminal punishment since the Code of Hammurabi. There are different definitions of legal insanity in different jurisdictions. A finding of insanity usually results in the defendant being confined in a mental health facility instead of a prison. The first to use this defense was Daniel Sickles when he killed his wife's lover Francis Barton Key (son of Francis Scott Key) in 1859.