This chapter redefines the problem of hospitals in the medieval church. It surveys the spread of welfare foundations to the West and, especially, the intensive foundation of welfare houses, in many forms, during the ‘charitable revolution’ of the twelfth and thirteenth centuries. This messy picture of hospitals on the ground, ‘between church and world’, has never conformed to the legal model that historians have long held for hospitals, as ecclesiastical houses under the bishop (a model that rests fundamentally on the sixth-century laws of Justinian, the East Roman/Byzantine Emperor). This gap between the ‘theory’ and ‘practice’ of hospitals, so familiar in scholarship, has long been attributed to lax enforcement—and a general lack of concern—by bishops, popes, and canonists. This chapter redefines the problem as the model itself, which was established by early twentieth-century historians. It unpicks this model, identifying the national agendas that produced it and the frameworks that have continued to shape the field. It argues for canon law as a European question and for the place of welfare at the heart of medieval Christianity. The overall approach and structure of the book is then introduced.