An article on VOX by Guy Michaels and Ferdinand Rauch looks at whether towns in France and Britain are “poorly located.” The authors explain that being in the wrong place — with poor access to world markets and resources, or vulnerability to natural disasters — has dire economic and social consequences. Examining historical evidence from the Roman Empire and the Middle Ages, they found that towns in France stayed put, while those in Britain moved:
Medieval towns in France were much more likely to be located near Roman towns than their British counterparts (Figure 1). These differences in persistence are still visible today: only three of the 20 largest cities in Britain are located near the site of Roman towns, compared to 16 in France. This finding suggests that the British urban network shifted towards newly advantageous locations, while French towns remained in locations, which may have become obsolete.
They also found coastal access to be important:
We find that during the Middle Ages towns in Britain were roughly two and a half times more likely to have coastal access – either directly or via a navigable river – than during the Roman era. In contrast, in France there was little change in the urban network’s coastal access over the same period. Moreover, we show that having coastal access was associated with faster town growth from 1200-1700, and that for towns with poor coastal access, access to canals was associated with faster population growth.
These findings, and the high costs of building and maintaining canals, suggest that access to water transportation was invaluable. The conclusion we draw is that many French towns were stuck in the wrong places for many centuries. They could not take advantage of the new transportation technologies since they had poor coastal access; they were in locations that were designed to fit with the demands of Roman times and not the considerations of the Middle Ages.