[Sidenote: Vitruvius.] A work of no literary excellence, but of great value on account of the information it contains, is the treatise _On Architecture_ (_De Architectura_), in ten books, by Vitruvius Pollio. Vitruvius was a practical architect, who built a basilica at Colonia Fanestris and had charge of the construction of machines of war under Augustus.[90] His books appear to have been written between 16 and 13 B. C., and dedicated to Augustus. They form the only systematic treatise on architecture preserved to us from antiquity, and are for that reason of the greatest importance to architects and archæologists. The style is, however, inelegant and obscure, though its obscurity is due in part to the necessary employment of technical expressions. Vitruvius was evidently a man of no great literary education or ability, however able he may have been as an architect. The age of Augustus is marked by the highest development of Roman poetry. Virgil, Horace, Tibullus, Propertius and Ovid are, each in his own way, the greatest of the Roman poets. Only Catullus and Lucretius can be compared with any one of them. The only great prose writer of the period is Livy. His style is still pure, and is certainly very charming; but even Livy departs somewhat from the dignity and beauty of the _sermo urbanus_, the Latin of Cicero and Cæsar. The extracts preserved by Seneca show that the rhetorical teaching of the time was artificial and tasteless, and was leading the way to decline, to the so-called silver Latin of the imperial epoch. BOOK III _THE EMPIRE AFTER AUGUSTUS_ CHAPTER XIII TIBERIUS TO VESPASIAN The emperors (Tiberius, 14-37 A. D.; Caligula, 37-41 A. D.; Claudius, 41-54 A. D.; Nero, 54-68 A. D.)—Phædrus, about 40 A. D.—Germanicus, 15 B. C.-19 A. D.—Velleius Paterculus, 30 A. D.—Valerius Maximus, about 47 B. C. to about 30 A. D.—Celsus about 35 A. D.—Votienus Montanus, died 27 A. D.—Asinius Gallus, 40 B. C.-33 A. D.—Mamercus Scaurus, died 34 A. D.—Publius Vitellius, died 31 A. D.—Domitius Afer, 14 B. C.-59 A. D.—Cremutius Cordus, died 25 A. D.—Aufidius Bassus—Remmius Palæmon—Julius Atticus—Julius Gracchinus—Marcus Apicius—Philosophers—Lucius Annæus Seneca, about 1 A. D. to 65 A. D.—Persius, 34-62 A. D.—Lucan, 39-65 A. D.—Calpurnius, about 60 A. D.—Pomponius Secundus, about 50 A. D.—Petronius, died 66 A. D.—Quintus Curtius, about 50 (?) A. D.—Columella, about 40 A. D.—Mela, about 40 A. D.—Other writers.