The time of the Macedonian dynasty was marked by intense cultural activity in the field of learning, literature, education, and art. The activity of such men as Photius in the ninth century, Constantine Porphyrogenitus in the tenth, and Michael Psellus in the eleventh, with their cultural environment, as well as the revival of the High School of Constantinople, which was reformed in the eleventh century, created favorable conditions for the cultural renaissance of the epoch of the Comneni and Angeli. Enthusiasm for ancient literature was a distinctive feature of the time. Hesiod, Homer, Plato, the historians Thucydides and Polybius, the orators Isocrates and Demosthenes, the Greek tragedians and Aristophanes and other eminent representatives of various sections of ancient literature were studied and imitated by the writers of the twelfth century and the beginning of the thirteenth. This imitation was particularly evident in the language, which, in its excessive tendency towards the purity of the ancient Attic dialect, became artificial, grandiloquent, sometimes hard to read and difficult to understand, entirely different from the living spoken tongue. It was the literature of men who, as the English scholar Bury said, were the slaves of tradition; it was a bondage to noble masters, but still it was a bondage. But some writers expert in the beauty of the classic tongue nevertheless did not neglect the popular spoken language of their time and left very interesting specimens of the living tongue of the twelfth century. Writers of the epoch of the Comneni and Angeli understood the superiority of Byzantine culture over that of the western peoples, whom a source called those dark and wandering tribes the greater part of which, if they did not receive birth from Constantinople, were at least raised and nourished by her, and among whom neither grace nor muse takes shelter, to whom pleasant singing seems the cry of vultures or croak of crow.