The history of the repair of these walls from time to time is a long one. For while comparatively secure from injury by the accidents of war, they were liable to be rudely shaken by earthquakes, like other public buildings of the city, while their proximity to the sea exposed them in a special manner to damage by damp and storm.

During the earlier days of the Empire, indeed, when the Imperial navy ruled the sea, and no hostile fleet dared approach the city, the condition of these fortifications was often neglected; but as the sea-power of the Empire decayed, and that of other nations grew stronger, the defences along the shores of the city assumed greater interest, and their maintenance in proper order became one of the principal cares of the State.

The earthquake of 447, so ruinous to the new land wall of Anthemius, injured also the seaward walls, especially the portion beside the Sea of Marmora. As an inscription over Yeni Kapou[[623]]—the gate at the eastern end of Vlanga Bostan—proclaimed, the damage was repaired by the Prefect Constantine when he restored the other fortifications of the city which had suffered from that terrible earthquake.[[624]]

There is no record of repairs for the next two hundred and fifty years. But the state of these walls could not have been altogether unsatisfactory during that period, for they were prepared to withstand two fleets which threatened the southern side of the city in the seventh century: first, when the ships of Heraclius came, in 610, to overthrow the tyranny of the infamous Phocas; and again, when the Saracens besieged Constantinople from 673-678.

With the accession of Tiberius Apsimarus the shore defences entered upon a new era of their history. Admiral of the Imperial fleet in the Ægean when the Saracens marched victoriously from the banks of the Nile to the Atlantic, and alive to the power of the enemy upon the sea, as well as upon land, he was in a position to appreciate the necessity of being ready to repel attack at every point. Hence, upon his return to Constantinople, he ordered the walls of the capital, which had for some time been grossly neglected, to be put into a state of defence.[[625]] Some eight years later, however, Anastasius II. found it expedient to attend to the seaward walls again,[[626]] in view of the formidable preparations made by the Saracens for their second attack upon the capital of Eastern Christendom; and so effective was the work done, that, in the great crisis of 718, the city defied a fleet of 1200 vessels.

In the spring of 764 an unusual occurrence shook the walls about the point of the Acropolis. The preceding winter had been one of Arctic severity. If the figures of Theophanes may be trusted, the sea along the northern and western shores of the Euxine was frozen to a distance of one hundred miles from land, and to a depth of sixty feet; and upon this foundation of solid ice a mass of snow forty-five feet high accumulated. As soon as the breath of spring liberated the frost-bound waters, a long procession of ice-floes came filing down the Bosporus, on their way to the southern seas. They came in such numbers that they packed in the narrow channel, and formed an ice-pile at the opening into the Sea of Marmora, extending from the Palace of Hiereia (Fener Bagtchessi) to the city, and from Chrysopolis to Galata, and as far as Mamas at the head of the Golden Horn.[[627]]

At length the ice divided again, and as its several parts swayed in the swollen currents, one huge iceberg came dashing against the pier at the point of the Acropolis. Another, larger, followed, and hurled itself against the adjacent wall with a violence which shook the whole neighbourhood. The monstrous mass was broken by the concussion in three fragments, still so large that they overtopped the city bulwarks and invested the apex of the promontory from the Mangana to the Port Bosporus, overawing the city, and crushing, it would appear, the fortifications.

Extensive repairs of these walls were commenced in the reign of Michael II., and completed by his son Theophilus on a scale which amounted to a work of reconstruction.[[628]] Under the former emperor the rebel Thomas had besieged the city and forced the chain across the entrance of the Golden Horn, proving, for the first time, that even the fortifications in that quarter might be attacked by a bold enemy. The Saracens, moreover, displaying new vigour, had taken Sicily and Crete, and in 829 defeated the Imperial fleet in the Ægean. Accordingly, it is not strange that Theophilus ordered the old ramparts along the shores of the city to be replaced by loftier and stronger fortifications, and that in the execution of the undertaking he spared no labour or expense. “The gold coins of the realm,” says the chronicler, “were spent as freely as if worthless pebbles.”[[629]]

The satisfaction of Theophilus with the result was displayed in the extraordinary number of the inscriptions which he placed upon the new walls and towers, to commemorate his work. No other emperor has inscribed his name upon the walls so frequently. And the fortifications he erected endured, with but little change, to the last days of the Empire, and bear his stamp even in their ruin.

Of the inscriptions referred to, the following are found on the walls along the Sea of Marmora: