 Complete the following phrase:  The greatest advantage of cannons over other siege weapons was the ability to fire a heavier projectile, farther, faster, and more often than previous weapons. They could also fire projectiles in a straight line, so that they could destroy the bases of high walls. Thus, old fashioned walls  that is, high and, relatively, thin  were excellent targets, and, over time, easily demolished. In 1453, the great walls of Constantinople, the capital of the Byzantine Empire, were broken through in 