Some notice, however brief, may here be taken of the wall erected by the Emperor Anastasius I. to increase the security of the capital, and at the same time to protect from hostile incursions the suburbs and a considerable tract of the rich and populous country, outside the Theodosian Walls. This additional line of defence, consisting of a wall twenty feet thick flanked by towers, stood at a distance of forty miles to the west of the city, and was carried from the shore of the Sea of Marmora to the shore of the Black Sea, across a territory fifty-four miles broad, or, as Procopius measures it, what would take two days to traverse. [1306] It was known, in view of its length, as the Long Wall (Μακρὸν τεῖχος), [1307] the Long Walls (τὰ Μακρὰ τείχη), [1308] and, after the emperor by whom it was erected, as the Anastasian Wall (τὸ τεῖχος τὸ Ἀναστασιακὸν). [1309] In 559, in the reign of Justinian the Great, it demanded extensive repairs on account of injuries due to earthquakes, and occasion was then taken to introduce a change which, it was hoped, would render the defence of the wall an easier task. All tower-gateways permitting communication between the towers along the summit of the wall were built up, so that a tower could be entered only by the gateway at its base; the object of this arrangement being to make every tower an independent fort, which could hold out against an enemy even after he was in possession of the wall itself. [1310] The Anastasian Wall appears in history in connection with the attacks of the Huns and Avars, in the reigns of Justinian the Great, [1311] Maurice, [1312] and Heraclius. [1313] But it cannot be said to have been of much service. The attempt to obstruct the march of the enemy, and to join issue with him at a distance from the city, was indeed a wise measure. It has been imitated by the recent establishment, nearer the city, of a chain of forts across the promontory, from Tchataldja to Derkos; a line of defence occupying a position which makes Constantinople, in the judgment of a competent military authority, [1314] the best-fortified capital in the world. But the weakness of the Anastasian Wall was its great length, which required for its proper defence a larger garrison than the Empire was able to provide for the purpose. [1315] And, of course, it was useless against an enemy advancing upon the capital by sea. [1316] Traces of the wall are, it is said, visible at Koush Kaya and at Karadjakeui.