Marcus Vitruvius Pollio (; c. 80–70 BC – after c. 15 BC), commonly known as Vitruvius, was a Roman author, architect, civil and military engineer during the 1st century BC, known for his multi-volume work entitled De architectura. His discussion of perfect proportion in architecture and the human body led to the famous Renaissance drawing by Leonardo da Vinci of Vitruvian Man. He was also the one who, in 40 BCE, invented the idea that all buildings should have three attributes: firmitas, utilitas, and venustas, meaning: strength, utility, and beauty. These principles were later adopted by the Romans.
Little is known about his life, but by his own description Vitruvius served as an artilleryman, the third class of arms in the military offices. He probably served as a senior officer of artillery in charge of doctores ballistarum (artillery experts) 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 Caesar's chief engineer Lucius Cornelius Balbus.
Vitruvius' works were largely forgotten until 1414, when De architectura was "rediscovered" by the Florentine humanist Poggio Bracciolini in the library of Saint Gall Abbey. Leon Battista Alberti published it in his seminal treatise on architecture, De re aedificatoria (c. 1450). The first known Latin printed edition was by Fra Giovanni Sulpitius in Rome, 1486. Translations followed in Italian, French, English, German, Spanish and several other languages. The original illustrations had been lost and the first illustrated edition was published in Venice in 1511 by Fra Giovanni Giocondo, with woodcut illustrations based on descriptions in the text.