In times gone by it was not uncommon for the aristocracy to keep a fool or halfwit, sometimes referred to locally as a "Hal", for their entertainment.
Unlike jesters who were entertainers by profession, Hals were known as natural fools or innocents. These were individuals that today would be termed to have learning difficulties and it was this trait that was exploited as a source of entertainment.
Today this sounds fairly appalling, but in a time when the prospects for anyone born with a disability were rather bleak, being taken in and provided for might have been some small blessing. No doubt some were kept and literally treated like pets, even being given a keeper, but by the 18th century the practice had taken on a more benevolent nature whereby the gentry could be seen to be caring for the afflicted.
During the mid 1700's one such individual called Hal Pierson was taken in as a child and reared by the family of Sir George Armytage of Kirklees Hall on the boundary of Mirfield and Brighouse.