The Latin element in the town took the chief part in the defense; not only were one-third of the soldiers from the West, but the galleys in the harbor, the weapons used, the stores for the siege, all were from the Occident. Only one of the towers on the city walls was in charge of a Greek, and the keys of the four chief city gates were kept by the Venetians. Catalans and Genoese were also given responsible positions; even in the personal entourage of the Emperor, only a few Greek names are noted. When the siege opened, the character of Mohammed’s strategy was soon plain. He had no intention of making a general assault of the ordinary type; instead, his cannon were directed against weak spots in the wall, and the work of destruction began. An unsuccessful attempt, however, was made to surprise the garrison on the 17th of April, and the Sultan was greatly disappointed when his fleet came out worsted from a fight with the imperial ships, which issued from the harbor to protect the entrance of three or four Genoese vessels that were bringing in stores. While the walls on the land side were being bombarded, the part of the city touching the sea was threatened. Urban, imitating the Venetians, who had transported war galleys across the land to Lake Garda, brought some of the Turkish ships from Galata-Pera to the Golden Horn. All attempts to destroy this hostile flotilla failed; by its presence it divided the Christian forces, and kept the small army of Constantine from concentrating in any strength at a threatened point. When May came, the besieged population began to suffer from scarcity of food. The only hope of relief was to be looked for from Venice; for the other powers in the West had received Constantine’s appeals with only verbal promises, or with indifference. Yet even the Venetians proceeded with great deliberation. The twelve galleys that had been ordered to be sent to help Constantinople in February were only ready by May 7th, and the Admiral, Loredano, was given instructions to handle the Turks unaggressively. He was told not to engage in a battle with them unless forced to do so.