Rome’s was a politics of all five senses. It was a city of noise, of refuse and bodies in the street, of massive crowds, of massive construction, and a size and opulence not equaled in Europe again for more than a millennium. In maps and inscriptions, Rome was the center of the world. How did Rome become this way? This chapter looks to intercity relations to resolve this puzzle. The Roman Empire was in effect a network of cities in the core–periphery mode – the ultimate “consumer city” supplied by vast hinterlands. Lacking the perfect local environment, Rome imported the commodities – and people – needed to construct an alpha city. The city grew as haphazardly and violently as the Empire itself. The greater the resources of the Empire, the larger the foundation for Rome’s growth. This hit crisis point in the Late Republic, as an increasingly dispossessed agrarian peasantry migrated en-masse to cities alongside inhabitants from across the world. In short, the context for Rome’s growth was a hitherto unparalleled age of globalization in the first and second centuries CE.