What difference do cities make? How the urban – and place more generally – have contributed to historical processes is one of the questions that continually confront urban historians. Should towns and cities be regarded as no more than the backdrop against which events and developments – industrialization, social conflict, war – are played out? Or do cities and urbanism more widely possess agency? Do they (as many urbanists claim) have an active part to play in shaping how historical processes eventuate, why things happened in this way here and that way there? If so, what precisely is the urban variable; how can we define and estimate it?