The "Regola delli cinque ordini d'architettura" is a treatise on the five classical orders of architecture: Doric, Ionic, Corinthian, Tuscan, and Composite. Written by Giacomo Barozzi da Vignola in the 16th century, it serves as a guide for architects and builders, detailing the proportions and decorative elements of each order. This work emphasizes the importance of symmetry and harmony in architectural design. Vignola's rules have influenced Western architecture significantly, providing a framework for creating aesthetically pleasing structures that adhere to classical principles. The treatise remains a key reference in architectural education and practice.