Greece, continued ever true to the principles of its great Athenian master. A chief part of the two years during which Cicero travelled in Greece and Asia was spent at Rhodes, and his principal teacher of eloquence at Rome was Molo the Rhodian, from whom he likewise afterwards received lessons at Rhodes. The great difficulty which that rhetorician encountered in the instruction of his promising disciple, was, as Cicero himself informs us, the effort of containing within its due and proper channel the overflowings of a youthful imagination(352). Cicero’s natural fecundity, and the bent of his own inclination, preserved him from the risk of dwindling into ultra-Attic slenderness; but it is not improbable, that from the example of Hortensius and his own copiousness, he might have swelled out to Asiatic pomp, had not his exuberance been early reduced by the seasonable and salutary discipline of the Rhodian. Cicero, in his youth, also wrote the _Rhetorica, seu de Inventione Rhetorica_, of which there are still extant two books, treating of the part of rhetoric that relates to invention. This is the work mentioned by Cicero, in the commencement of the treatise _De Oratore_, as having been published by him in his youth. It is generally believed to have been written in 666, when Cicero was only twenty years of age, and to have originally contained four books. Schütz, however, the German editor of Cicero, is of opinion, that he never wrote, or at least, never published, more than the two books we still possess. A number of sentences in these two books of the _Rhetorica, seu de Inventione_, coincide with passages in the _Rhetoricum ad Herennium_, which is usually published along with the works of Cicero, but is not of his composition. Purgold thinks that the _Rhetor. ad Herennium_ was published first, and that Cicero copied from it those corresponding passages(353). It appears, however, a little singular, that Cicero should have borrowed so largely, and without acknowledgment, from a recent publication of one of his contemporaries. To account for this difficulty some critics have supposed, that the anonymous author of the _Rhetor. ad Herennium_ was a rhetorician, whose lectures Cicero had attended, and had inserted in his own work notes taken by him from these prelections, before they were edited by their author(354). Some, again, have imagined, that Cicero and the anonymous author were fellow-students under the same rhetorician, and that both had thus adopted his ideas and expressions; while others believe, that both copied from a common Greek original. But then, in opposition to this last theory, it has been remarked, that the Latin words employed by both are frequently the same; and there are the same references to the history of Rome, and of its ancient native poets, with which no Greek writer can be supposed to have had much acquaintance.