The Janissaries were trained to act either as cavalry or infantry. They carried bows and small wooden shields, and were further armed with a long lance or with a scimitar. The Anatolian division was composed mostly of cavalry. Leonard, however, points out that though the cavalry were numerous they fought as infantry. Philelphus, who was a contemporary envoy at the Porte, states that the Anatolian troops were armed with scimitars, maces, and small shields. The great superiority of the Turks as regards arms was in the cannon. While, as we have seen, the besieged could not use such cannon as they had for fear of destroying the walls from which they were fired, the Turk was under no such disadvantage, and was entirely up to date with the very latest improvements in heavy guns. The siege of Constantinople in fact marks an era in the employment of large cannon and gave to the world the first noteworthy intimation that the stone walls of the Middle Ages constituted no longer a secure defence. Cannon had, indeed, been known a century and a half earlier in Western Europe, and had been employed both by and against the Turks on the Danube;[280] but the astonishment which the introduction of large cannon caused at the siege of Constantinople shows that while the invention itself was new to the people of the East, its development was hardly less surprising to those of the West. Critobulus remarks upon the siege that ‘it was the cannon which did everything.’ So novel was the invention that he gives a detailed account of the casting of one of the big guns, and explains how the powder was made, how the gun was mounted and loaded, and how it fired its stone ball. ‘When fire is applied to the touch-hole, the powder lights quicker than thought. The discharge makes the earth around it to tremble, and sends forth an incredible roar. The stone ball passes out with irresistible force and energy, strikes the wall at which it has been aimed, overthrows it, and is itself dashed into a thousand pieces.’ No wall was so hard or had such power of resistance that it could withstand the shock. Such is the incredible and unthinkable nature of the machine to which, as the ancient tongue had no name for it, he suggests that of helepolis or ‘Taker of Cities.’