Byzantine art, from the sixth century to the present time, has exerted a wide influence. Sicily, southern Italy, Rome, Ravenna, and Venice contain many examples of Byzantine churches. Italian painting in the Middle Ages seems to have been derived directly from the mosaic pictures of the artists of Constantinople. Russia received not only its religion but also its art from Constantinople. The great Russian churches of Moscow and Petrograd follow Byzantine models. Even the Arabs, in spite of their hostility to Christianity, borrowed Byzantine artists and profited by their services. The Mohammedan mosques of Damascus, Cairo, and Cordova, both in methods of construction and in details of ornamentation, reproduce Byzantine styles. LITERATURE AND LEARNING The libraries and museums of Constantinople preserved classical learning. In the flourishing schools of that city the wisest men of the day taught philosophy, law, medicine, and science to thousands of students. The professors figured among the important persons of the court: official documents mention the "prince of the rhetoricians" and the "consul of the philosophers." Many of the emperors showed a taste for scholarship; one of them was said to have been so devoted to study that he almost forgot to reign. When kings in western Europe were so ignorant that they could with difficulty scrawl their names, eastern emperors wrote books and composed poetry. It is true that Byzantine scholars were erudite rather than original. Impressed by the great treasures of knowledge about them, they found it difficult to strike out into new, unbeaten paths. Most students were content to make huge collections of extracts and notes from the books which antiquity had bequeathed to them. Even this task was useful, however, for their encyclopedias preserved much information which otherwise would have been lost. During the Middle Ages the East cherished the productions of classical learning, until the time came when the West was ready to receive them and to profit by them. 119. CONSTANTINOPLE POSITION OF CONSTANTINOPLE The heart of Byzantine civilization was Constantinople. The city lies on a peninsula between the Sea of Marmora and the spacious harbor called the Golden Horn. Washed on three sides by the water and, like Rome, enthroned upon seven hills, Constantinople occupies a site justly celebrated as the noblest in the world. It stands in Europe, looks on Asia, and commands the entrance to both the Mediterranean and the Black Sea. As a sixteenth century writer pointed out, Constantinople "is a city which Nature herself has designed to be the mistress of the world." [Illustration: Map, VICINITY OF CONSTANTINOPLE] CONSTANTINOPLE AS A NATURAL CITADEL