The arrangement of the subject-matter is as follows: Book i., sciences on which architecture is based, chief divisions of the subject, choice of site, and method of laying out a town; ii., building materials; iii., temples--Ionic order; iv., Doric and Corinthian orders; v., public buildings, _e.g._, forum, theatre; vi., private houses--construction; vii., decoration; viii., water-supply; ix., methods of measuring time, _e.g._, sun-dials; x., engines and machines used in war and in the arts. The work is dedicated to Augustus, who is addressed throughout, and is meant to be of practical use to him in his building operations. The body of the work is severely technical; the introductions to the Books are in a more ambitious style. Vitruvius writes as a professional man, not as a scholar: i. 1, 17, 'Non uti summus philosophus nec rhetor disertus nec grammaticus summis rationibus artis exercitatus, sed ut architectus his litteris imbutus haec nisus sum scribere.' He freely confesses his obligations to Greek authors, whom he enumerates vii. praef. 10-14. Diagrams were appended to the text: i. 6, 12, 'Quoniam haec a nobis sunt breviter exposita, ut facilius intellegantur visum est mihi in extremo volumine formas, sive uti Graeci σχήματα dicunt duo explicare.' SENECA THE ELDER. (1) LIFE. Annaeus Seneca (for the praenomen Marcus, usually given, there is no authority: in the best MSS. it is Lucius, possibly through confusion with his son) was a native of Corduba: Mart. i. 62, 7, 'Duosque Senecas unicumque Lucanum facunda loquitur Corduba.' The date of his birth is probably about B.C. 55, for he was old enough to have heard Cicero if the civil wars had not prevented him leaving his native town: _Contr._ i. praef. 11, 'Omnes magni in eloquentia nominis excepto Cicerone videor audisse: ne Ciceronem quidem aetas mihi eripuerat, sed bellorum civilium furor, qui tunc orbem totum pervagabatur, intra coloniam meam me continuit.' He was of equestrian rank; cf. the speech of Seneca the younger, Tac. _Ann._ xiv. 53, 'Egone, equestri et provinciali loco ortus, proceribus civitatis adnumeror?' Most of his life appears to have been spent in Rome, where alone he could have acquired his vast knowledge of contemporary rhetoric. Together with his countryman Porcius Latro, he attended the lectures of the rhetorician Marullus: _Contr._ i. praef. 22, 'Hoc Latro meus faciebat, ut sententias amaret. Cum condiscipuli essemus apud Marullum rhetorem ...' Asinius Pollio he had heard at two different periods: _Contr._ iv. praef. 3, 'audivi illum et viridem et postea iam senem.' Seneca's wife was Helvia, whose noble character is described by her son (_ad Helv._ 14, 3; 16, 3): by her he had three sons, M. Annaeus Novatus, L. Annaeus Seneca, and M. Annaeus Mela.