BYZANTINE ART takes its name from Byzantium, the Greek city on the Bosporus of which Constantine the Great made a capital in A.D. 324. For the next 'Jo() oo years, Constanti nople was the centre of the Greek civilization that produced By zantine art. Signs of a forthcoming revolution in plastic ideas occur before the foundation of Constantinople, such as the f our porphyry emperors set in an outer wall of S. Mark's at Venice (c. A.D. 30o), whose simple planes bring out the quality of the material with a new technique. But it is characteristic of the transitional period that these figures are still scowling, close cropped soldiers, and it was only after Constantinople had received its name that the imperial semblance itself was composed in accordance with the new aesthetic principles. On the coins pro duced not only at Constantinople but by the other Greek mints, the new type may be seen in its purity, while western coins at tempt the imitation of the Greek style. In portrait sculpture, enough fragments remain to show that the movement there was parallel. Religious art, meanwhile, gradually divested itself of the well-worn stock of formulae, taken over from antiquity, common in Early-Christian sarcophagi and wall paintings. It took, however, two centuries for Byzantine principles to extend to the whole field, religious art included, and even so they only triumphed completely in the Greek parts of the empire.