De Officiis

My dear son Marcus, you have now been studying a full year under Cratippus, and that too in Athens, and you should be fully equipped with the practical precepts and the principles of philosophy; so much at least one might expect from the pre-eminence not only of your teacher but also of the city; the former is able to enrich you with learning, the latter to supply you with models. Nevertheless, just as I for my own improvement have always combined Greek and Latin studies—and I have done this not only in the study of philosophy but also in the practice of oratory—so I recommend that you should do the same, so that you may have equal command of both languages. And it is in this very direction that I have, if I mistake not, rendered a great service to our countrymen, so that not only those who are unacquainted with Greek literature but even the cultured consider that they have gained much both in oratorical power and in mental training.