THE BULWARK ON THE BOSPORUS
WITH THE end of antiquity, the greatest period of the cities was over; the period of the largest cities, on the other hand, was just beginning.
In point of population, the ancient cosmopolitan cities were surpassed during the Middle Ages only in the Far East; in point of splendour, right up to the present only in Asia. No city ever again has played such a predominant rôle as Rome or Babylon.
The decline of Rome brought 5,500 years of city history to an end. Since then, only 1,500 years have passed. The era of ancient world cities -- that is, the period from Hammurabi's Babylon to the victory of the Germanic tribes -- lasted 2,000 years; of this period, 900 years, from 600 B.C. to A.D. 300, saw the greatest flowering of these cities. The industrial city culture of our days has been in existence for only 150 years. Such figures should put us on guard against losing our perspective and seeing the distant past as shorter than it actually was.
In regard to city history, the Mddle Ages in Europe were a protracted and mostly vain attempt to regain the prominence which the cities of antiquity had achieved. To be sure, this attempt was attractive enough as it was, and brought forth a number of charming results from Lübeck in northern Germany to Florence in Italy.
With the break-up of the Roman imperium, the centre of gravity of city culture moved from the Mediterranean area to Asia, especially to China and India, and into the Islamic world, while weeds grew among the ruins of European cities. In the early Middle Ages, the only world city of Europe was situated on the very edge of the continent, just half a mile away from Asia on the other side of the Bosporus. The city, of course, was Constantinople, earlier named Byzantium, and today Istanbul. As Byzantium it had its beginning in the seventh century B.C. as a Greek colony and became Roman in 201 B.C. It was a strong fortress, one that could control navigation from the Mediterranean into the Black Sea and passage to Asia at the narrowest point of the strait. Its location was obviously ideal not only for a fortress but also for a commercial centre -- and it was also exceedingly beautiful, on a hilly peninsula created by the deep-