When Mars Meets Euclid: The Relationship between War and Mathematical Sciences in Frontispieces of Fortification Treatises

War and mathematics are at the heart of a common discourse since the first theoretical treatises appeared on the printed book market. Just as early modern mathematicians did not hesitate to underline the effectiveness of mathematical sciences in the art of war to entrench their legitimacy, fortification theorists did the same by reinforcing the geometrical aspect of military architecture and siege warfare. At a time when the production of fortification treatises can be seen as an attempt to ennoble military architecture, their frontispieces, as a window to the knowledge contained in the book, turn out to be the most suitable place to expose this relationship between war and mathematics that becomes more and more intimate throughout the modern period. If several studies have already explored title pages of mathematical treatises, those of military literature did not generate the same degree of interest. Thus, this paper aims to shed new light on fortification treatises frontispieces by focusing on how they staged the bond between war and mathematics to legitimize the science of fortress building. More specifically, based on a few major case studies from the French, Dutch and German markets, this article intends to investigate the visual strategies and the models used in these title pages – in comparison with the ones adopted in mathematical treatises – to promote the new art of war on both artistic and intellectual level.