A fourth lost work of Cicero, is his _Hortensius sive de Philosophia_. Besides the orator after whom it is named, Catulus, Lucullus, and Cicero himself, were speakers in the dialogue. In the first part, where Hortensius discourses, it was intended to exalt eloquence above philosophy. To his arguments Cicero replied, showing the service that philosophy rendered to eloquence, even in an imperfect state of the social progress, and its superior use in an improved condition of society, in which there should be no wrong, and consequently no tribunals of justice. All this appears from the account given of the _Hortensius_ by St Augustine, who has also quoted from it many beautiful passages--declaring, at the same time, that it was the perusal of this work which first inspired him with a love of wisdom.--"Viluit mihi repente omnis vana spes, et immortalitatem sapientiæ concupiscebam æstu cordis incredibili(483)." This dialogue continued to be preserved for a long period after the time of St Augustine, since it is cited as extant in his own age by the famous Roger Bacon(484).
It was not till after the æra of Augustus, that works originally destined for the public assumed the name and form of letters. But several collections of epistles, written, during the period on which we are now engaged, to relatives or friends in private confidence, were afterwards extensively circulated. Those of Cornelia, the daughter of the elder Scipio Africanus, and mother of the Gracchi, addressed chiefly to her sons, were much celebrated; but the most ample collection now extant, is that of the Letters of Cicero.
These may be divided into four parts,--1. The Epistolæ Familiares, or Miscellaneous Correspondence; 2. Those to Atticus; 3. To his brother Quintus; 4. To Brutus.
The correspondence, usually entitled _Ad Familiares_, includes a period of about twenty years, commencing immediately after Cicero's consulate, and ending a few months before his death. The letters which this collection comprehends, are so extremely miscellaneous, that it is impossible even to run over their contents. Previous to the battle of Pharsalia, it chiefly consists of epistles concerning the distribution of consular provinces, and the political intrigues relating to that constantly recurring subject of contention,--recommendatory letters sent with acquaintances going into the provinces--details to absent friends, with regard to the state of parties at Rome, particularly the designs of Pompey and Cæsar, and the factions of Milo and Clodius; and, finally, entertaining anecdotes concerning the most popular and fashionable amusements of the Capital.