Mahomet, however unwilling to break with the Genoese, was not content to have communication between the two divisions of his fleet interrupted. Accordingly, once more he renewed his attempt to destroy the boom. Barbaro appears Renewed attempt on May 21. to have been on one of the ships defending it. On May 21 at two hours before daylight, the whole fleet moved out from the Double Columns and with great noise of drums and trumpets came down the Bosporus. All on board the Christian vessels were greatly alarmed, but dispositions for the defence were taken, and, as it was feared that contemporaneously a general attack upon the city was about to be made, the alarm bells rang out and every one took his allotted station either on shore or on the ships. Once more the Turks decided that it was hopeless to attempt the destruction of the boom, and therefore returned to their moorings. It is impossible to say whether the Turks really believed that they might destroy it or whether the three attempts just mentioned were merely feints to tire out the besieged and alarm them by a display of overwhelming force. It is certain, however, that the Venetian and Greek sailors were always ready to resist, and that, after this attempt on May 21, Mahomet’s fleet made no further attempt to force its way into the harbour.
Attempts to undermine the walls.
Already, on May 16, the besieged had discovered that the Turks were attempting to undermine the walls and thus enter into the city. Zagan Pasha, the renegade Albanian, in command of Mahomet’s army in Pera and opposite the walls from Caligaria to the Horn, had under him a number of miners, who had been brought from Novo Brodo in Serbia and who possibly were Saxons brought to that country to work in the silver mines. These men took in hand the task of undermining. They commenced their work at a distance sufficiently far removed not to be observed by the besieged. Probably the first place attacked was between the Adrianople Gate and Tekfour Serai. They endeavoured to undermine the foss and the Outer Wall.[336] When this failed a second attempt was made against the walls of the quarter called Caligaria, and this, says Barbaro, because in that place there were no enclosures or, as he calls them, ‘barbicans,’ the wall being single and unprotected even by a ditch. This description enables us to identify the place as the wall running at right angles to the northern end of the foss. An Austrian named John Grant, who acted under the Grand Duke, took charge of the counterminers and succeeded in finding and entering the Turkish mine, where he and his men burnt the props. The works fell in and suffocated a number of Turkish workmen. The incident greatly alarmed the citizens, who feared that on future occasions Grant might not be fortunate enough to discover the mine before the Turks had entered by it or had blown up a part of the walls. Fortunately, the rocky character of the ground prevented the miners from meeting with any notable success. Phrantzes states that the only damage done by the Turks in mining was to destroy part of an old tower, which was soon repaired by the defenders.[337]
Construction of a turret, May 18.
At daylight on May 18, the citizens were astonished to see a wooden turret or ‘bastion,’ which had been built during the night.[338] The turret had been constructed with the same secrecy and celerity that Mahomet invariably adopted in the execution of his plans. Barbaro declares that all the Christians in the city could not have made it under a month. It was a huge structure. It was only in the morning, when they saw it complete in a place where no preparations had been observed on the previous evening, that they realised what had been done. This ancient form of the ‘Taker of Cities’ was stationed near the Romanus Gate. It consisted of a strong framework of long beams so high as to overlook the Outer Wall.[339] It had been partly filled with earth, faced with a threefold covering of camels’ or bullocks’ hides, and was built on wheels or rollers. Steps led to its upper platform. These and the road which led to the camp, which was sufficiently distant to be out of range, were also covered for protection. Scaling-ladders could be raised and thrown from the summit of the turret to that of the wall. If the huge machine was, as Barbaro states, within ten paces of the wall, it must have been built in the foss itself. It dominated the outer barbican or enclosure and would have allowed the enemy under cover of its protection to fill the ditch from three openings which were in the side presented to the walls and to undermine them in safety. The latter probably was the principal object for which it was intended. It would also have enabled the Turks to prevent the besieged from repairing the damages to the Outer Wall caused by the cannon. For this reason we can understand the statement of Barbaro, that while it gave increased hope to the Turks, it filled the besieged with alarm. It was built, according to Tetaldi, opposite the place defended by Justinian.[340] Its dangerous character was soon shown. The cannon having destroyed one of the towers near the Romanus Gate, the turret was moved and stood overhanging the ditch. A fierce fight took place between the Turks inside it and the Greeks and Italians under Justiniani. The Turks flung earth, wood, and all kinds of material available into the foss, employing mainly the stone from the ruined tower, so as to form a level pathway across. The besieged fought hard from daylight till after sunset to prevent the Turks from making use of the turret, and the emperor and Justiniani assisted all the night at the repair of the tower.
It was probably the fact that the ditch had been largely filled with brushwood which brought about the destruction of the machine. The besieged managed to place barrels of powder in the ditch, set fire to the brushwood, and blew up the whole structure. Several of its occupants perished in the explosion. At daylight the sultan found that his huge turret was reduced to ashes, that the foss had been cleared out, and that the ruined tower had been in great part repaired. He swore that the thirty-seven thousand prophets could not have persuaded him that the besieged could have compassed its destruction in so short a time.[341]
A similar turret was erected opposite the Pegè Gate, or, what is more probable, opposite the Third Military Gate, and possibly there were others near the Golden Gate and elsewhere.[342]
Further attempts to undermine.
Undeterred by the discovery and failure of the attempt to undermine the walls at Caligaria, the Turks made other trials in the same neighbourhood. But Grant was always ready, countermined and destroyed the enemies’ work before they could use it. On three successive days mines were found in this place, ‘where there were no barbicans,’ but they also were destroyed, and a number of Turks, who could not escape in time, either lost their lives or were captured.
On the 24th, a mine was found which had apparently been more carefully concealed. A wooden turret had been built near the walls, which was intended to serve the double purpose of deceiving the besieged into supposing that its object was to facilitate the actual scaling of the walls, while at the same time it rested on a bridge of logs beneath which excavation was being made. It contained the earth and stones which were taken out. The ruse was, however, suspected, and the counterminers found and destroyed the mine.