The Papal State and the Birth of the Modern Fortress: Innovation in Military Construction between the Late Middle Ages and the Early Modern Period

Abstract

Transformations from the fifteenth to the sixteenth centuries, particularly focusing on the emergence of the angular bastion trace. It argues that this “modern style” of fortification was not merely a response to advances in weaponry but a generative force that reshaped political communities, especially evident in the Papal States. Drawing on Paolo Prodi’s seminal work, the study highlights how these military innovations contributed to the Papal States becoming a prototype of the early modern State. The analysis traces the evolution of papal fortification policy from the mid-fourteenth century, examining initiatives under Cardinal Albornoz and subsequent popes, including significant projects like Rocca Pia and Matteo Nuti’s designs. The “Borgia moment” under Alexander VI is emphasized as a period of unprecedented quantitative and qualitative innovation, characterized by a centralized defensive network and cutting-edge architectural advancements, notably at Nettuno. The essay then details the continuity of this strategic vision under Julius II and Clement VII, despite periods of conflict, illustrating the ongoing integration of military infrastructure with broader state-building objectives. Finally, it notes that this intense period of design and construction preceded the formal codification of fortification treatises, underscoring a unique channel of knowledge transmission.