In the mid-1960s, writer John Berger and photographer Jean Mohr profiled John Sassall, general practitioner in the Forest of Dean, photographing and documenting his everyday practice. The passage above describes the difficulty of providing an accurate medical prognosis to a terminally ill patient. Medical prognosis has always been, at best, an inexact science. There are also a multitude of ethical considerations to take into account when providing a prognosis. If someone is told ‘you have six months to live’ is that likely to make them give up hope and lose the will to carry on, dying sooner? Or will it make them more likely to live their last months to the full, cherishing every last moment? What if you instruct them to make a will, and dealing with the reality of their demise kills them sooner than you predicted? But what if they don't make a will and die, leaving their next of kin to have to sort things out? Is it ever acceptable to lie to a patient, even if you think it is for their own benefit?

These considerations and anxieties around sickness and death are not a consequence of the modern age and biomedicine. Late medieval Europe was intimately concerned with preparing for death. And, despite the difficulties surrounding accurate prediction, medical prognosis was a major branch of medieval medicine, and was one of the physician's main tools in a medical culture where treatment was often ineffective, surgery a dangerous last resort and diagnosis difficult.2 With the rise of university medicine and the emergence of the educated physician in the thirteenth and fourteenth centuries, learned medicine became a commercial enterprise, and a physician's ability to prognosticate successfully demonstrated his skill and secured his status.