Vitruvius

A Roman engineer and architect serving under Julius Caesar and Augustus, Vitruvius authored *De architectura* ("Ten Books on Architecture") around 30–15 BC — the only major architectural treatise to survive from classical antiquity.

His three Vitruvian principles — *firmitas*, *utilitas*, *venustas* (durability, utility, beauty) — became the bedrock of Western architectural thought. The treatise rediscovered in 1414 ignited the Italian Renaissance's classical revival; his canon of human proportion inspired Leonardo's Vitruvian Man.