Under the category ‘Tolerated prisons’ Defoe numbered Bedlam and fifteen private ‘mad-houses’. Despite being places of confinement he was drawing a distinction between them and ordinary prisons. Although from early on the distinction between the mad and the sad and the mad and the bad has been maintained, the mentally ill and those with a criminal mentality have always been linked. Both groups were detained in coercive institutions, be they gaols for criminals where the ill were cast in with the evil, hospitals for ‘lunatics’ (as they were called) such as Bedlam, asylums for the criminally insane such as Broadmoor, therapeutic centres within prisons for violent sociopaths, such as the Barlinnie Special Unit, or the only entirely therapeutic prison for the socially and psychologically disturbed, HMP Grendon.

The priory of St Mary of Bethlehem – or Bethlem – was founded in 1247 outside Bishopsgate but just within the City. It existed for prayer and to raise alms for the crusades, but soon took on the roles of caring for the poor, providing lodging for travellers and offering hospitality to visiting dignitaries. It thus became a hostel or ‘hospital’, but not in the clinical sense of being a specialised institution for the care of the sick. After a century of obscurity it was taken ‘under the protection and patronage’ of the mayor and aldermen of the City of London. Financially more secure and having survived the ravages of the Black Death, around 1400 it first began taking in ‘distracted persons’ and has continued in this task to the present day, making it Europe's oldest extant psychiatric hospital.