Guarino Guarini and the "Fortificatione" between theory, drawing and design

[EN] During his stay in Turin as an architect and engineer at the Savoy court, Guarini addresses the issue of fortifications. In those years, in fact, he also works in the field of military buildings, despite being predominantly engaged, both on theoretical and practical ambit, in civil and religious architecture. Dates back to the 1676, the publication of the Trattato di Fortificatione, one of his lesser known works, while his design for the 'Gate of Po' is realized since 1674. In the Trattato, Guarini proposes a set of rules, based on Euclidean geometry, drawn from observation of several military buildings in France, Holland and Italy. These basic principles provide graphical methods to outline the fortifications plan, during the concept phase. Then Guarini teaches to represent and render three-dimensional images of the conceived fortress. This paper aims to highlight, using tools of graphic analysis and history of representation, Guarini's contributions to the issue of fortifications crossing information obtained from his theoretical and practical works.