One of the problems of urban history is the fearsome range of expertise that the urban historian is supposed to appreciate, if not master. Belaboured, rightly, by archaeologists, geographers, and architectural historians, we have begun to open our eyes to the evidence of the physical environment of medieval towns, but that is not the half of it. In order to understand urban institutions one needs to be a religious historian, an economic historian, a legal historian; and if one were ever to make sense of everything that is included in the ‘social history’ of towns, then social anthropology, historical demography, and sociology are only three of the battery of foglamps that would be needed to penetrate our cloud of unknowing. The subject which I now wish to add to the list of those we are supposed to cover does not even have the attraction of sounding new and modish and exciting. The history of political thought has, after all, formed a part of undergraduate history courses in this country ever since they began, and it is traditionally one of the least popular and least satisfactory parts of them, especially for the sort of students who may go on to be interested in urban history: those who relish the exact, the local detail, the reality of topography, the ability to connect the documents of the past with visible phenomena in the present.