In his treatment of cities, Manuel Castells (1996: 386) considers them to be ‘not a place but a process’. By this he means ‘a process by which centres . . . are connected in a global network’. This is a very important idea and it should not be restricted to conceptualizing today’s global cities. If cities in general are a process in this Castellian sense, then it follows that there can be no such entity as ‘the city’, meaning a single city. Cities are networks; individual cities within networks have hinterlands but the latter are never sufﬁcient to create and maintain an ‘isolated city’. The latter is a myth that appears in archaeology in the search for the ﬁrst city, sometimes called the ‘mother city’, in a region. There is no such process of one city initially standing alone but whose success then diffuses the idea of ‘the city’ throughout a region. It is city networks that are constructed in any urbanizing region: there are always multiple ‘mother cities’. Cities need each other. Similarly, the single city at the centre of von Thunen’s famous ‘isolated state’ is an abstraction deﬁning a situation that could not happen. Even capital cities need other cities.