Early and late, in his court and in his cabinet, the young Sultan could talk of nothing but the approaching siege.  With the writing-reed and a scroll of paper in his hand he was often seen tracing plans of the fortifications of Constantinople, and marking out positions for his own batteries.  Every question relating to the extent and locality of the various magazines to be constructed in order to maintain the troops was discussed in his presence; he himself distributed the troops in their respective divisions and regulated the order of their march; he issued the orders relating to the equipment of the fleet, and discussed the various methods proposed for breaching, mining, and scaling the walls.  His enthusiasm was the impulse of a hero, but the immense superiority of his force would have secured him the victory with any ordinary degree of perseverance.

The Ottomans were already familiar with the use of cannon.  Amurath II had employed them when he besieged Constantinople in 1422; but Mahomet now resolved on forming a more powerful battering-train than had previously existed.  Neither the Greeks nor Turks possessed the art of casting large guns.  Both were obliged to employ foreigners.  An experienced artilleryman and founder named Urban, by birth a Wallachian, carried into execution the Sultan’s wishes.  He had passed some time in the Greek service; but, even the moderate pay he was allowed by the Emperor having fallen in arrear, he resigned his place and transferred his services to the Sultan, who knew better how to value warlike knowledge.  He now gave Mahomet proof of his skill by casting the largest cannon which had ever been fabricated.  He had already placed one of extraordinary size in the new castle of the Bosporus, which carried across the straits.  The gun destined for the siege of Constantinople far exceeded in size this monster, and the diameter of its mouth must have been nearly two feet and a half.  Other cannon of great size, whose balls of stone weighed one hundred fifty pounds, were also cast, as well as many guns of smaller calibre.  All these, together with a number of ballistae and other ancient engines still employed in sieges, were mounted on carriages in order to transport them to Constantinople.  The conveyance of this formidable train of artillery, and of the immense quantity of ammunition required for its service, was by no means a trifling operation.

The first division of the Ottoman army moved from Adrianople in February, 1453.  In the mean time a numerous corps of pioneers worked constantly at the road, in order to prepare it for the passage of the long train of artillery and baggage wagons.  Temporary bridges, capable of being taken to pieces, were erected by the engineers over every ravine and water-course, and the materials for every siege advanced steadily, though slowly, to their destination.  The extreme difficulty of moving the monster cannon with its immense balls retarded the Sultan’s