Vitruvius served under Julius Cæsar in Africa as a military engineer; and was subsequently employed by one of the emperors, to whom his treatise is dedicated, in the direction and control of that department of the public service. By his favour, and the kindness of his sister, he was thus placed in a condition, if not of affluence, at least of competency. Who his imperial patron was has been disputed; but the widely extended conquests, the augmentation of the empire, the political institutions, and, moreover, the taste for architecture which Vitruvius attributes to him, renders it most probable that it was Augustus, the sovereign who found the city of bricks and left it of marble. It is clear that his work was written after the death of Julius Cæsar, and not later than that of Titus, for the former he prefixes the word Divus, whilst he does not mention the Coliseum; and, although he speaks of Vesuvius,[997] he is evidently not aware of any eruptions having taken place except in ancient times. Notwithstanding the arguments adduced by W. Newton[998] to prove that he wrote in the reign of Titus, it is now universally admitted that Vitruvius was a writer of the Augustan age. The inferiority of his style to that of his contemporaries, its occasional obscurity and want of method, the not unfrequent occurrence of inelegant, and even barbarous expressions, notwithstanding his classical education, may be accounted for by what has already been stated respecting the professional object of all his studies. He himself claims indulgence on this score,[999] and states that he writes as an architect, and not as a literary man. So much of its difficulty as arises from conciseness he considers a matter for boasting rather than apology. In forming an estimate of the Latinity of an author like Vitruvius, it must not be forgotten that our taste is formed by authority and by a study of the best models. Novelty is exceptional, and therefore displeases. But technical subjects render not only the introduction of new terms necessary, but even, owing to the poverty of language, awkward periphrases and obscure phraseology. Nevertheless, upon the whole, the language of Vitruvius is vigorous, his descriptions bold, and seem the work of a true and correct hand, and a practised draughtsman. His work consists of ten books, in which he treats of the whole subject in a systematic and orderly manner.