This was shown in the very first siege, 626, as well as in the last; and it was here that the first cannonade was directed against the walls, in 1422. In the last siege two towers of the inner wall and a large part of the outer wall were battered to pieces, and the moat was filled ready for an assault. Giustiniani erected a palisade covered with hides and supported with earthworks; and it was not till the gallant Genoese fell mortally wounded that the Turks succeeded in forcing their way in.

It is through the Edirnè Kapoussi that one naturally enters to see both the Church of the Chora and the Tekfour Serai, the palace of the Porphyrogenitus. The large mosque within the gate is that built by Suleiman in memory of one of his daughters.

Continuing northwards, with the striking view of the ruined palace rising above the walls, we reach the sixth military gate, and beyond this the lines of the walls, which have turned eastwards, are much broken. The sixth military gate is the Kerko-Porta (see above p. [150]).

Beyond this the wall of Theodosius comes to an end abruptly. From this point the fortifications have a different character. "Along the greater portion of their course these bulwarks consisted of a single wall, without a moat; but at a short distance from the water, where they stand on level ground, they formed a double wall, which was at one time protected by a moat and constituted a citadel at the north-west angle of the city." They belong, Professor van Millingen has also clearly proved, to at least three periods, to the days of Heraclius, of Leo, and of Manuel Comnenus. After the Kerko-Porta the Theodosian walls turned eastwards; when the palace of Blachernae was defended it was probably by the erection, after the fifth century, of a new wall. The wall of Manuel Comnenus, built to give additional protection, left the earlier wall on an inner line of defence.

The wall of Manuel is stronger than that of Theodosius, but it has no moat; it resisted all the efforts of the Turkish artillery in 1453. The public gate in it was that of the Kaligaria (the district where military shoes were made), and from a tower beside it the last Emperor and Phrantzes reconnoitred early in the morning of the last day of the siege. North of this, from the tower which stands at the point where the wall turns eastwards, the fortifications seem to have been entirely rebuilt during the repairs of the fourteenth and fifteenth century. In this piece stands the gate of Gyrolimnè, through which probably the leaders of the Crusaders in 1203, who were encamped on the hill just outside, entered to negotiate with Isaac Angelus. Behind it stood the palace of Blachernae, the site of which may be expected to reveal much when it is excavated.

Beyond this, from the great tower, unbattlemented, which has on it an inscription in honour of Isaac Angelus, who reconstructed it in 1188, the greatest difficulties surround the identification of the different portions. The first part of the wall is of great height—sometimes sixty-eight feet—and of thickness varying from over thirty to over sixty feet. Three towers protect this part: two "twin towers" rising to a great height above the walls. The special character of the walls is determined by the fact that, within, the palace of Blachernae stood upon a terraced hill. The second tower, much higher than that with the inscription, may be identified with the tower of Isaac Angelus, described by Nicetas Choniates as built by the Emperor both for the defence of Blachernae, and for a residence for himself. Beyond it is a third tower, which has been generally considered to be the tower of Anemas, mentioned first by Anna Comnena, as the place in which Anemas, who had conspired against her father, was confined.

All these identifications are difficult; and it is also difficult to feel sure that a more satisfactory solution of the many problems which arise would not be to consider that the tower of Isaac Angelus is the comparatively small one that still bears his inscription, and that the two others, and northern tower, combine to form the "prison of Anemas."

Within these towers was certainly the Palace of Blachernae, and the chambers now so grim and foul, that may sometimes be inspected, are very likely the prisons built by Alexius Comnenus and connected with his palace.

Beyond these towers a new series of walls begins. These are "in two parallel lines, connected by transverse walls, so as to form a citadel beside the Golden Horn. The inner wall belongs to the reign of Heraclius; the outer is an erection of Leo V. the Armenian." A splendid view of these magnificent walls, and of the Golden Horn below, is obtained from the hill westwards, on which the Crusaders encamped in 1203. The wall of Heraclius, with its three hexagonal towers, was built to protect the suburb of Blachernae after the attack of the Avars in 627: that of Leo was built in 813 when the city was in danger from the Bulgarians. A citadel was formed between the two walls, within which was the chapel and sacred well of S. Nicholas. The gate is the gate of Blachernae, and beyond it is a tower with an inscription stating that it was reconstructed by "Romanus, the Christ-loving sovereign." From this point a wall led to the water's-edge, and in it was the Wooden Gate (Ξυλόπορτα, see above, p. [273]).

We have thus completed the circuit of the most interesting mediæval defences in Europe. At every point they have memories that go back to great historic days, memories of treachery as well as heroism, but above all of a long and gallant defence of all that made the civilization of Europe enduring and worthy to endure.