In the genteel world of Regency England, madness was not truly  a medical diagnosis—it was a legal and social crisis. If the patriarch of an estate began to show signs of mental decline, it was not only a family tragedy but a potential threat to the continuity of property and inheritance. In my novel, The Mercy of Chance, a variation of Pride and Prejudice, this delicate question moves to center stage when the Bennet sisters find themselves managing Longbourn after their father’s death, while their elderly grandfather—the legal owner of the estate—is accused of madness by a grasping cousin.

I found the most interesting source on The Old Bailey..