Following our exploration of Ghiberti, this lecture shifts focus to his great rival, Filippo Brunelleschi, the visionary architect who ushered the transition from Gothic building traditions to the harmonious rationality of the Renaissance. We will dissect his groundbreaking solutions to structural challenges, most notably the ingenious double-shell construction of the dome for Florence Cathedral—a feat that defied the engineering limits of his time—while also examining the serene, mathematically proportioned interiors of San Lorenzo and Santo Spirito. By analysing his rediscovery of classical principles and his invention of linear perspective, we will reveal how Brunelleschi not only transformed the skyline of Florence but fundamentally altered the way Western civilisation perceived space and structure.