According to Immanuel Wallerstein, the sixteenth century saw the emergence of a capitalist world economy in which labor was organized on a global scale, and the production, distribution and use of goods and services were integrated across national boundaries. This article argues that, though exceptional, an integrated, hegemonic division of labor on an international scale did occur before 1500. Adopting one of Wallerstein’s conceptual tools, the commodity chain approach, it analyzes the production, distribution and industrial use of alum, a chemical compound, from the thirteenth to the sixteenth centuries. The high-quality cloth industry of the Low Countries, the most prominent artisanal sector of the period in Europe, strongly relied on alum as a mordant to fix colors. Yet the best varieties of alum could only be won in Asia Minor until the middle of the fifteenth century and in central Italy after 1450. The combination of the inflexible demand structure and the mineral’s limited supply resulted in the creation of commodity chains that crossed national and even continental boundaries and allowed those in control of the alum mines to establish exactly those dependency relations that were particular to Wallerstein’s world economy of the sixteenth century. If the aim is to study the conditions in which economic actors lived and worked and the ways in which they organized their labor, a focus on the production contexts of specific commodities, rather than on comprehensive world systems, might therefore be more revealing.