(which Vitruvius dedicated to Augustus), nor by the little that is known of Mamurra. Vitruvius was a military engineer (praefectus fabrum), or a praefect architectus armamentarius of the apparitor status group (a branch of the Roman civil service). He is mentioned in Pliny the Elder's table of contents for Naturalis Historia (Natural History), in the heading for mosaic techniques. Frontinus refers to "Vitruvius the architect" in his late 1st-century work De aquaeductu. Likely born a free Roman citizen, by his own account Vitruvius served in the Roman army under Caesar with the otherwise poorly identified Marcus Aurelius, Publius Minidius and Gnaeus Cornelius. These names vary depending on the edition of De architectura. Publius Minidius is also written as Publius Numidicus and Publius Numidius, speculated as the same Publius Numisius inscribed on the Roman Theatre at Heraclea. As an army engineer he specialized in the construction of ballista and scorpio artillery war machines for sieges. It is speculated that Vitruvius served with Caesar's chief engineer Lucius Cornelius Balbus. The locations where he served can be reconstructed from, for example, descriptions of the building methods of various "foreign tribes". Although he describes places throughout De Architectura, he does not say he was present. His service likely included north Africa, Hispania, Gaul (including Aquitaine) and Pontus. To place the role of Vitruvius the military engineer in context, a description of "The Prefect of the camp" or army engineer is quoted here as given by Flavius Vegetius Renatus in The Military Institutions of the Romans: The Prefect of the camp, though inferior in rank to the [Prefect], had a post of no small importance. The position of the camp, the direction of the entrenchments, the inspection of the tents or huts of the soldiers and the baggage were comprehended in his province. His authority extended over the sick, and the physicians who had the care of them; and he regulated the expenses relative thereto. He had the charge of providing carriages, bathhouses and the proper tools for sawing and cutting wood, digging trenches, raising parapets, sinking wells and bringing water into the camp. He likewise had the care of furnishing the troops with wood and straw, as well as the rams, onagri, balistae and all the other engines of war under his direction. This post was always conferred on an officer of great skill, experience and long service, and who consequently was capable of