The city of Piacenza in northern Italy offers a remarkable example of the impact of an architectural project on the political, urban, and economic fabric of a medieval city. The ambitious design of the church of San Francesco causes us to rethink the traditional history of mendicant architecture; its patronage complicates the relationship between church and state in the late Middle Ages. My dissertation proposes that the Franciscans and their church both reflected and stimulated changes in the economic structures of the protocapitalist city. Taking into account contemporary documents, I will illuminate the building’s impact on the city’s institutions and individuals. As an historian of medieval architecture and urbanism, I will demonstrate how the Franciscan construction and bold architectural choices participated in the reordering of the political and urban topography of Piacenza, reconfiguring the city’s tenuous balance between religious and civic institutions, while creating a new civic center.