Historical Embeddedness and Complex Contagions in the Adoption of the Reformation

In this article we use network theory to explain the adoption of the Protestant Reformation.
We use new historical data on the connections between Hansa towns that allow
us to conduct the first social network study of the Protestant Reformation. Based on an
analysis of cities in central and Western Europe between 1517 and 1530, we find evidence
for diffusion through both simple and complex contagion. Our operationalization of network
data based on medieval Hansa Diets points to the complex association between
tie weights (i.e., the strength of ties) and numbers of ties in network diffusion. Using
optimal tuning parameters for simple adoption models, we show that a combination of
strong ties and weak ties fostered Protestant adoption in northern cities.