Mohammed thought nothing dear in exchange for Constantinople: and lavished gold and honors on the refugee. "Can you found me a piece sufficiently like a thunderbolt that a ball launched from it may shake the walls of Constantinople?" "I can found you one," replied the Hungarian, "that would overthrow the walls of Babylon." A foundry was established at Adrianople, the metal was prepared, and at the end of three months Urban produced a piece of brass ordnance of stupendous and almost incredible magnitude. The stone bullet was of twelve palms circumference and weighed twelve hundred pounds. Before its trial the population were warned of the coming event. The explosion was felt or heard in the circuit of an hundred furlongs, the ball was driven above a mile and buried itself a fathom in the ground. It required a force of a hundred oxen and seven hundred men to move it, and nearly two months were consumed in dragging it one hundred and fifty miles to Constantinople. In the spring of 1453 two hundred thousand men from Asia, and two hundred thousand from Europe assembled rapidly in the vast plains that extend from Gallipoli to Constantinople under the eye of the Sultan, Khalil and his generals. The land and the sea supplied them in abundance for all the wants of the army; while a fleet of one hundred and sixty vessels of war, many of them but small ones, cruised about in full view of the tents upon the sea of Marmora. Constantine, the Emperor, must have been mad to hope to defend a city some thirteen miles in extent, when a careful enumeration showed only four thousand nine hundred and seventy Romans: to which were added some five or six thousand strangers under the command of John Justiniani, a noble Genoese. No capital had been more favored by nature than Constantinople for defence against the investment and the assault of an entire people. Geography had made it a citadel, a thousand years of power in its emperors and of art in its engineers had completed the work of nature. Nature had made a peninsula, policy an island, the hills a fortress. The Greek Empire as if it had foreseen that one day it would fall, seemed to have meant to confine all its monuments, all its masterpieces, all its riches in an Acropolis at the extreme point of the continent of Europe where it fled the barbarians to encounter the Conquerors. While fear was falling upon the hearts of Byzantines presentiments of glory cheered the hearts of the soldiers of Mohammed through the sole prophecy of the Koran. "Know you the city," says the Koran, "of which two sides look upon the sea and one side upon the land? It will fall, not beneath the force of the enginery of war, but before the omnipotence of these words: 'There is no other God but God, and God alone is great.'"