In literature too the average capacity of this aristocracy was high, though the greatest literary figures of the age, if we except Caesar, do not, strictly speaking, belong to it; Cicero was a novus homo, and Lucretius and Catullus were not of the senatorial order. But the new education, as we shall see later on, was admirably calculated to train men in the art of speaking and writing, if not in the habit of independent thinking; and among the nobles who reaped the full fruits of this education every one could write in Latin and probably also in Greek, and if he aimed at public distinction, could speak without disgracing himself in the senate and the courts. Oratory was, in fact, the staple product of the age, and the chief _raison d'être_ of its literary activity. Long ago the practice had begun of writing out successful speeches delivered in the senate, in the courts, or at funerals; the means of publication were easy, as a consequence of the number of Greek slaves who could act as copyists, and thus oratory formed the basis of a prose literature which is essentially Roman,[165] rooted in the practical necessities of the life of the Roman noble, though deeply tinged with the Greek ideas and forms of expression acquired in the process of education in vogue. Treatises on rhetoric, the art of effective expression in prose, form an important part of it; two of them still survive from the time of Sulla,--the _Rhetorica ad Herennium_ of an unknown author, and Cicero's early treatise _de Inventione_. Later on Cicero wrote his admirable dialogue _de Oratore_ and other works on the same subject, ending with his _Brutus_, a catalogue raisonnée, invaluable to us, of all the great Roman orators down to his own time.