<p>This study presents a geometric analysis of the macsura vaults of the Mosque–Cathedral of Córdoba, focusing on the reconstruction of their underlying design principles. Based on high-resolution three-dimensional data, the methodology combines geometric reconstruction with metric validation to investigate the relationship between design and built form. The results reveal a coherent geometric framework defined through elementary operations executable with simple drafting instruments, such as the straightedge, square, and compass. Within this system, variations between central and lateral vaults are interpreted as controlled adaptations of a unified geometric logic. The high correspondence between reconstructed and measured geometry indicates that the vaults can be explained through geometric definition rather than empirical adjustment. Dimensional relationships further support the plausibility of the cubit as part of the design process.</p>