[Sidenote: Grammar, literature, and philosophy.] The study of grammar was diligently pursued in the second century, and with it went the writing of commentaries on the classical authors. Under Hadrian, Terentius Scaurus wrote a Latin grammar, part of which is preserved in an abbreviated form, as well as commentaries on Plautus, Virgil, and Horace, fragments of which are found in the works of later commentators. Under the Antonines, rhetoricians and grammarians were numerous, and discussions of literary and grammatical questions formed a considerable part of polite conversation. Metrical handbooks were written by Terentianus Maurus and Juba, Helvius Acro wrote commentaries on Terence, Horace, and Persius about the end of the second century, and Pomponius Porphyrio, a grammarian of distinction, whose scholia on Horace still exist, though not in their original form, wrote probably at the end of the second or the beginning of the third century. Festus, who made an epitome of Verrius Flaccus (see page 166) probably lived but little after this time. Some of the rhetoricians of this period probably continued to teach as they had themselves been taught, but the most important among them developed a new school, which will form the subject of our next chapter. Philosophy had in the second century still many followers, but there was little literary production in Latin. Dio Chrysostom, Plutarch, Marcus Aurelius, and Sextus Empiricus wrote in Greek. CHAPTER XVII LITERARY INNOVATIONS Fronto, about 100 to about 175 A. D.—Gellius, born about 125 A. D.—Apuleius, about 125 to about 200 A. D.—Innovations in poetry—The _Pervigilium Veneris_.