Among the writers on applied science, one of considerable eminence has descended to us, the architect VITRUVIUS POLLIO. He is very rarely mentioned, and has been confounded with Vitruvius Cerdo, a freedman who belongs to a later date, and whose precepts contradict in many particulars those of the first Vitruvius. His birth-place was Formiae; he served in the African War (46 B.C.) under Caesar, so that he was born at least as early as 64 B.C. [56] The date of his work is also uncertain, but it can be approximately fixed, for in it he mentions the emperor's sister as his patroness, and as by her he probably means Octavia, who died 11 B.C., the book must have been written before that year. As, moreover, he speaks of one stone theatre only as existing in Rome, whereas two others were added in 13 B.C., the date is further thrown back to at least 14 B.C. As he expressly tells us it was written in his old age, and he must have been a young man in 46 B.C., when he served his first campaign, the nearer we bring its composition to the latest possible date (_i.e._ 14) the more correct we shall probably be. He was of good birth and had had a liberal education; but it is clear from the style of his work that he had either forgotten how to write elegantly, or had advanced his literary studies only so far as was necessary for a professional man. [57] His language is certainly far from good. He began life as a military engineer, but soon found that his personal defects prevented him from succeeding in his career. [58] He therefore seems to have solaced himself by setting forward in a systematic form the principles of his art, and by finding fault with the great body of his professional brethren. [59] The dedication to Augustus implies that he had a practical object, viz. to furnish him with sound rules to be applied in building future edifices and, if necessary, for correcting those already built. He is a patient student of Greek authors, and adopts Greek principles unreservedly; in fact his work is little more than a compendium of Greek authorities. [60] His style is affectedly terse, and so much so as to be frequently obscure. The contents of his book are very briefly as follows:-- Book I. General description of the science--education of the architect--best choice of site for a city—disposition of its plan, fortifications, public buildings, &c. " II. On the proper materials to be used in building, preceded, like several of Pliny's books, by a quasi-philosophical digression on the origin and early history of man--the progress of art--Vitruvius gives his views on the nature of matter. " III. IV. On temples--an account of the four orders, Doric, Ionic, Corinthian, and Composite. " V. On other public buildings. " VI. On the arrangement and plan of private houses. " VII. On the internal decoration of houses.