Memoirs were written in the Neronian age by numbers both of men and women. Those of the Empress Agrippina were used by Tacitus; and we have references to others by the two great Roman generals of the period, Suetonius Paulinus and Domitius Corbulo. The production of scientific or technical treatises, which had been so profuse in the preceding generation, still went on. Only two of any importance are extant; one of these, the _Chorographia_ of Pomponius Mela, a geographical manual based on the best authorities and embellished with descriptions of places, peoples, and customs, is valuable as the earliest and one of the most complete systems of ancient geography which we possess; but in literary merit it falls far short of the other, the elaborate work on agriculture by Lucius Junius Moderatus Columella. Both Mela and Columella were natives of Spain, and thus belong to the Spanish school of Latin authors, which begins with the Senecas and is continued later by Martial and Quintilian. But while Mela, in his style, followed the new fashion, Columella, an enthusiast for antiquity and a warm admirer of the Augustan writers, reverts to the more classical manner, which a little later became once more predominant in the writers of the Flavian period. His simple and dignified style is much above the level of a mere technical treatise. His prose, indeed, may be read with more pleasure than the verse in which, by a singular caprice, one of the twelve books is composed. In one of the most beautiful episodes of the _Georgics_, Virgil had briefly touched on the subject of gardening, and left it to be treated by others who might come after him: _praetereo atque aliis post me memoranda relinquo_. At the instance, he says, of friends, Columella attempts to fill up the gap by a fifth Georgic on horticulture. He approaches the task so modestly, and carries it out so simply, that critics are not inclined to be very severe; but he was no poet, and the book is little more than a cento from Virgil, carefully and smoothly written, and hardly if at all disfigured by pretentiousness or rhetorical conceits.