Recent literature in the world-systems perspective has refocused attention on questions of ‘core’ and ‘periphery’ in historical capitalism, yet rarely critically examines the underlying assumptions regarding these zones. Drawing on a developing dataset on the world’s wealthiest individuals (the World-Magnates Database), we trace the development and expansion of sugar circuits across the Atlantic world from the sixteenth through the eighteenth centuries to explain how the sugar commodity chain leads us to rethink some prevailing notions of core and periphery. Namely, we challenge the notion that these zones consist of geographical spaces that, since very early in the development of the world-economy, became permanently specialized in the production of raw materials (periphery) or more sophisticated manufactures (core); and that labor forces have been trans-historically relatively free/better-paid in core activities and coerced/poorly-paid in peripheral ones. We argue that, prior to the nineteenth century, the world-economy is not only characterized by the uneven and combined emergence of various forms of labor exploitation, as usually argued within a world-systems perspective, but also one in which core-like and peripheral activities (that is, those providing access to relatively greater or lesser wealth) were not yet as clearly bounded geographically as they would become in the nineteenth and twentieth centuries. We find that a longue-durée analysis of sugar production by enslaved labor illustrates not merely processes of peripheralization, but of what we call coreification.