Columella flourished in the reigns of Claudius and Nero. He is author of an agricultural work, "De Re Rustica," in which he gives, in smooth and fluent, though somewhat too diffuse a style, the fullest and completest information on practical agriculture among the Romans in the first century of the Christian era. Frontinus (fl. 78 A.D.) left two valuable works, one on military tactics, the other a descriptive architectural treatise on those wonderful monuments of Roman art, the aqueducts. Besides these, there are extant fragments of other works on surveying, and on the laws and customs relating to landed property, which assign Frontinus an important place in the estimation of the students of Roman history. 9. ROMAN LITERATURE FROM HADRIAN TO THEODORIC (138-526 A.D.).--From the death of Augustus, Roman literature had gradually declined, and though it shone forth for a time with classic radiance in the writings of Persius, Juvenal, Quintilian, Tacitus, and the Plinies, with the death of freedom, the extinction of patriotism, and the decay of the national spirit, nothing could avert its fall. Poetry had become declamation; history had degenerated either into fulsome panegyric or the fleshless skeletons of epitomes; and at length the Romans seemed to disdain the use of their native tongue, and wrote again in Greek, as they had in the infancy of the national literature. The Emperor Hadrian resided long at Athens, and became imbued with a taste and admiration for Greek; and thus the literature of Rome became Hellenized. From this epoch the term classical can no longer be applied to it, for it no longer retained its purity. To Greek influence succeeded the still more corrupting one of foreign nations. With the death of Nerva, the uninterrupted succession of emperors of Roman or Italian birth ceased. Trajan himself was a Spaniard, and after him not only foreigners of every European race, but even Orientals and Africans were invested with the imperial purple, and the huge empire over which they ruled was one unwieldy mass of heterogeneous materials. The literary influence of the capital was not felt in the interior portions of the Roman dominions. Schools were established in the very heart of nations just emerging from barbarism; and though the blessings of civilization and intellectual culture were thus distributed far and wide, still literary taste, as it flowed through the minds of foreigners, became corrupted, and the language of the imperial city, exposed to the infecting contact of barbarous idioms, lost its purity. The Latin authors of this age were numerous, but few had taste to appreciate and imitate the literature of the Augustan age. They may be classified according to their departments of poetry, history, grammar and oratory, philosophy and science.