And he held that we should give thanks not only to those who teach rightly, but even to those who err, as affording the way of more easily investigating truth, as he plainly declares in the second book of his Metaphysics.

Thus many learned lawyers contributed to the Pandects, many physicians to the Tegni, and it was by this means that Avicenna edited his Canon, and Pliny his great work on Natural History, and Ptolemy the Almagest.
For as in the writers of annals it is not difficult to see that the later writer always presupposes the earlier, without whom he could by no means relate the former times, so too we are to think of the authors of the sciences.

For no man by himself has brought forth any science, since between the earliest students and those of the latter time we find intermediaries, ancient if they be compared with our own age, but modern if we think of the foundations of learning, and these men we consider the most learned.

What would Virgil, the chief poet among the Latins, have achieved, if he had not despoiled Theocritus, Lucretius, and Homer, and had not ploughed with their heifer?
What, unless again and again he had read somewhat of Parthenius and Pindar, whose eloquence he could by no means imitate?
What could Sallust, Tully, Boethius, Macrobius, Lactantius, Martianus, and in short the whole troop of Latin writers have done, if they had not seen the productions of Athens or the volumes of the Greeks?
Certes, little would Jerome, master of three languages, Ambrosius, Augustine, though he confesses that he hated Greek, or even Gregory, who is said to have been wholly ignorant of it, have contributed to the doctrine of the Church, if more learned Greece had not furnished them from its stores.

As Rome, watered by the streams of Greece, had earlier brought forth philosophers in the image of the Greeks, in like fashion afterwards it produced doctors of the orthodox faith.