"Three times did Mohammed the Conqueror ascend the Ottoman throne. Twice he had resigned it, a sullen and reluctant boy of fourteen, whom it was necessary to inveigle out of the way, lest he should resist his father to the face, when, to save the State, he appeared to resume his abdicated power. The third time, seven years older, he sprang on the great prize with the eagerness and ferocity of a beast of prey. He never drew bridle from Magnesia, when he heard of his father's death, till on the second day he reached Gallipoli, on his way to Adrianople. To smother his infant brother in the bath was his first act of power; and then he turned, with all the force of his relentless and insatiate nature to where the inheritor of what remained of the greatness of the Cæsars--leisurely arranging marriages and embassies--still detained from the Moslems the first city of the East;--little knowing the savage eye that was fixed upon him, little suspecting the nearness of a doom which had so often threatened and had been so often averted." It did not need the half-defiant attitudes of Constantine XII. to arouse the young Sultan: as soon as he had concluded a truce with his northern foes he began to make those elaborate preparations which should ensure success in the great conquest. His first act was to secure the isolation of the capital. Already he held the passage of the Dardanelles; now he would secure that of the Bosphorus. In 1393 Bayezid had built on the Asiatic shore, some five miles above Constantinople, the fortress which was the first distinct menace to the imperial city. Anadoli Hissar, the "Asiatic Castle," still stands overhanging the water's edge, a splendid mediæval building of four square towers with one great central keep. In 1452 a corresponding tower was begun on the other side of the sea, at the point where the passage is narrowest. The first stone was laid by Mohammed himself on March 26, 1452, and by the middle of August the castle was completed. The design of this Roumeli Hissar represented the name of the Prophet and the Sultan, the consonants standing out as towers. Protests were unheeded and the two envoys sent by the Emperor to remonstrate were butchered at once. A Venetian galley was sunk as it passed, to prove the range of the guns. Its crew were slain when they swam ashore. A Hungarian engineer was employed to direct a cannon foundry, and a vast store of materials of war was accumulated for the siege. After another winter's preparation all was ready, and early in the spring of 1453 a vast Turkish host[26] was ranged from the Golden Horn to the Marmora. The sea was covered by three hundred vessels and it seemed as if succour was cut off on every side. On April 6, 1453, the siege began.