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. To-day as one goes along the great triumphal way, still retaining fragments at least of its solid pavement that was laid by Justinian, the way along which countless armies of emperors and of invaders have passed on their march of triumph or retreat, we are reminded of the past not only by shattered walls, and by the goats that feed and scramble where once the soldiers of the empire kept watch, but by the immemorial cemetery, with its groups of cypress, which stands beside us as we walk.