Quintilian, Institutio Oratoria 2.5:
“Some have favorably recommended those minor authors because their sense seemed easier to grasp, but others have counseled beginning with the more ornate type of writing, as it is better suited to the nourishment of young minds. I would have the student read the best authors immediately and always, but of the best authors I would like to see them start with the clearest and most straightforward authors – for example, young boys should read Livy rather than Sallust, who, though he be a better historian, requires a completed education to understand. Cicero seems to me at any rate to be both pleasing even to neophytes and at least sufficiently clear in sense. His writing can be a source of both profit and pleasure. Afterward, as Livy recommends, the student should read whoever is most like Cicero.”
Nam quidam illos minores, quia facilior eorum intellectus uidebatur, probauerunt, alii floridius genus, ut ad alenda primarum aetatium ingenia magis accommodatum. Ego optimos quidem et statim et semper, sed tamen eorum candidissimum quemque et maxime expositum uelim, ut Liuium a pueris magis quam Sallustium (et hic historiae maior est auctor, ad quem tamen intellegendum iam profectu opus sit). Cicero, ut mihi quidem uidetur, et iucundus incipientibus quoque et apertus est satis, nec prodesse tantum sed etiam amari potest: tum, quem ad modum Liuius praecipit, ut quisque erit Ciceroni simillimus.