His first work, reckoning according to the chronological order of events, is the Jugurthine war, which commenced B. C. 111, and ended B. C. 106. The next period, comprehending the social war and the war of Sulla, extending as far as the consulship of M. Æmilius Lepidus, B. C. 78, had already been related by Sisenna, a friend of Cicero.[949] Where Sisenna left off, the Histories of Sallust (Historiarum Libri V.) began, and continued the narrative without interruption until the prætorship of Cicero.[950] This work is unfortunately lost, with the exception of some letters and speeches, and a few fragments relating to the war of Spartacus. Niebuhr[951] considers this one of the most deplorable losses in Roman literature; less, however, on account of its historical importance, than as a perfect model of historical composition. A break of two years ensues, and then follows the “_Bellum Catilinarium_,” or history of the Catilinarian conspiracy in the year of Cicero’s consulship.[952] This completes the list of those works which are undoubtedly genuine. No satisfactory opinion has been arrived at respecting the authorship of the two letters to Cæsar, “_De Republicâ Ordinandâ_;” and it is now unhesitatingly admitted, that the declamation against Cicero, must have been, as well as its counterpart, the declamation against Sallust, the work of some rhetorical writer of a later period. The subject of this imaginary disputation was naturally suggested by the known fact that Sallust was no friend to Cicero. It has already been stated that Sallust was a bitter opponent of the principles and policy of the aristocratic party; but it must be carefully explained what is meant by that assertion. The object of his hatred was not the old patrician blood of Rome, but the new aristocracy, which had of late years been rapidly rising up and displacing it.