Answer
Architectural principles are the main theme of Vitruvius' De architectura. This comprehensive work, written by the Roman architect Marcus Vitruvius Pollio in the 1st century BCE, explores the principles and practices of architecture, including the importance of symmetry, proportion, and harmony. Vitruvius believed that architecture should be both functional and aesthetically pleasing, and he emphasized the need for architects to have a thorough understanding of mathematics, engineering, and the arts.