The effects of political fragmentation on investments: A case study of watermill construction in medieval Ponthieu, France

The link between political fragmentation and economic development has been frequently discussed in the pre-modern growth literature, yet, it has mostly been treated in a general manner. This paper provides a specific and detailed case study of the patterns of watermill construction in the northern French region of Ponthieu, France. The results suggest that political fragmentation in the juridical context of medieval Europe positively affected investments in machinery. I concentrate on the eleventh and twelfth centuries, a period characterized by political fragmentation and weak central authority, and provide original evidence that watermill construction was significantly more intense in areas where authority was fragmented and landholding was divided between numerous landlords. I suggest that the mechanism behind the phenomenon is that in the institutional context of medieval Europe political fragmentation reduced the territorial extent of lords' jurisdiction and therefore, of their monopoly over watermill construction. This, in return, promoted the construction of neighboring watermills, thereby affecting the number of watermills and the level of competition in the milling industry.