Vitruvius was a Roman author, architect, and engineer during the 1st century BCE, best known for his multi-volume work entitled De Architectura. His writings were a central influence on the Renaissance and, in particular, on the Neoclassical style of architecture. His writings also had a strong impact on Renaissance mechanics, and are 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).