Epidemic Trade

Epidemic Trade

By Lars Boerner and Battista Severgnini

EHES Working Paper, No. 24 (September 2012)

Abstract: This paper studies the spread of the Black Death as a proxy for the intensity of medieval trade flows between 1346 and 1351. The Black Death struck most areas of Europe and the wider Mediterranean. Based on a modified version of the gravity model, we estimate the speed (in kilometers per day) of transmission of the disease between the transmitting and the receiving cities. We find that the speed depends on distance, political borders, and on the political importance of a city. Furthermore, variables related to the means of transportation like rivers and the sea, religious seasons such as Advent, and geographical position are of substantial significance. These results are the first to enable us to identify and quantify key variables of medieval trade flows based on an empirical trade model. These results shed new light on many qualitative debates on the importance and causes of medieval trade.

Excerpt: An interesting case which documents the unequal speed of the spread is related to the transmission of the infection from Florence, one of the largest important cities in Italy with about 100,000 inhabitants. After the outbreak of the plague in the Tuscan city at the beginning of March 1348 the Black Death moved during the same months to Bologna and Modena, about 110 and 160 kilometers away. In contrast, the virus took almost two months to reach Siena, just 70 kilometers from Florence. Even at rst glance it is dicult to identify the causes of this di erent timing. Benedictow claims that “the Black Death showed its ability to perform middle-range metastatic leaps along important commercial roads between large commercial and production centers in areas with great population density”. Thus the speed of the transmission might be explained by the di erent trade intensities between cities.

Click here to read this article from the European Historical Economics Society

Sign up to get a Weekly Email from

* indicates required

medievalverse magazine