This lecture discusses the evolution of military architecture and its impact on design principles from the Renaissance to modern times. It begins by examining the role of architectural orders in the Renaissance, highlighting the challenges architects faced in reconciling rational design with practical constraints. The instructor emphasizes the significance of military architecture, particularly during the 15th century, as a catalyst for the development of modern architectural design. The introduction of gunpowder and firearms transformed fortification strategies, leading to the creation of bastioned fortifications that prioritized depth over height. The lecture explores key figures such as Francesco di Giorgio and Antonio da Sangallo, who innovated in fortification design, emphasizing the importance of site adaptation and empirical approaches. The discussion also covers the organizational aspects of military architecture, including the collaboration between architects, engineers, and soldiers. Ultimately, the lecture illustrates how military architecture has shaped contemporary architectural practices and the concept of design as a rational process.