Marcus Vitruvius Pollio, commonly known as Vitruvius, was a Roman author, architect, and civil and military engineer during the 1st century BC, known for his multi-volume work entitled De architectura. He originated the idea that all buildings should have three attributes: firmitas, utilitas, and venustas. These principles were later widely adopted in Roman architecture. His discussion of perfect proportion in architecture and the human body led to the famous Renaissance drawing of the Vitruvian Man by Leonardo da Vinci.
Little is known about Vitruvius' life, but by his own description he served as an artilleryman, the third class of arms in the Roman military offices. He probably served as a senior officer of artillery in charge of doctores ballistarum and libratores who actually operated the machines. As an army engineer he specialized in the construction of ballista and scorpio artillery war machines for sieges. It is possible that Vitruvius served with Julius Caesar's chief engineer Lucius Cornelius Balbus.