Ten Books on Architecture - De architectura (English: On architecture, published as Ten Books on Architecture) is a treatise on architecture written by the Roman architect Marcus Vitruvius Pollio and dedicated to his patron, the emperor Caesar Augustus, as a guide for building projects. The work is one of the most important sources of modern knowledge of Roman building methods, as well as the planning and design of structures, both large (aqueducts, buildings, baths, harbours) and small (machines, measuring devices, instruments). It is also the prime source of the famous story of Archimedes and his bath-time discovery. Vitruvius - Marcus Vitruvius Pollio (born c. 80–70 BC, died after c. 15 BC), commonly known as Vitruvius, was a Roman author, architect, civil engineer and military engineer during the 1st century BC, known for his multi-volume work entitled De architectura. 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.