I will return to Plato and his followers when we come to consider the theories of education which the philosophers based on the phenomena of Greek history. And before we pass from the Sophists to the Rhetors, and show a further specializing of higher education in that direction, we may say a word in conclusion on the external history of these once celebrated, and since much-maligned, educators. We hardly know them at all, save through their enemies, the specialist philosophers and specialist rhetoricians; and what we hear of them must be distrusted and sifted accordingly. Nevertheless, even from their enemies, we learn that the three greatest of them--Protagoras, Gorgias, and Prodicus--were eminently respectable and respected men. So was the fourth in importance, Hippias, though the encyclopædic pretensions he put forth to practise all trades and manual dexterities, as well as philosophy, history, and rhetoric, have left an unpleasant impression against him. Nevertheless, he was honored at Elis, his native place, as their leading citizen, and compiled for them the annals of their famous past in such a way as to gain universal acceptance. As regards the other three, though they all professed to impart general education, and to give their pupils that negative training in philosophy which would arm them against false theories, yet they were each remarkable for some special line. Protagoras, apart from his famous philosophical position of the relativity of knowledge to him who knows, openly professed to teach _political_ wisdom, and despised all other kinds of knowledge in comparison with it. Gorgias, on the other hand, though he wrote a famous treatise with the very Hegelian title “concerning nature or the non-existent,” devoted his main attention to _rhetoric_, and was truly the father of technical Greek oratory. For though we hear of Corax and Tisias in Sicily, and of Empedocles, as having cultivated the art, the first recognized theorist and practical speaker was Gorgias. He not only delivered set speeches, but so trained himself as to deliver elegant discourses on any proposed subject, apparently without preparation, but of course with the help of a clever system of well-arranged commonplaces, which he applied with quickness and variety. The philosophy of Prodicus was chiefly ethical, and his apologues were very popular and quoted in after-days. But more important were his _grammatical_ studies, whereby he fixed the parts of speech, and laid the groundwork of the grammar of the modern languages of Europe. Indeed, the strict attention to form shown by all the Sophists led them to study language with peculiar care, and they were the forefathers of modern philologists in this as in some other respects.