National Geographic : 1946 Nov
Siege of a Walled City EAST of the Mediterranean, where Greek architectural traditions had introduced a highly advanced type of fortification, the Roman armies encountered enemies quite different from the forest-inhabiting barbarians of Europe-enemies who stood siege behind high walls with powerful projecting towers sheltering metal-reinforced gates. In the illustration the direct attack against the strongest part of the city defenses is largely a diversion; and the sapping at the left, under the "tortoise" of interlocked shields, is little more than a feint. Still, the de fenders on the walls strive mightily with javelins, arrows, and boulders to break up the Roman assault before the diggers succeed in tunneling be neath the foundations to open a breach in the tower or the wielders of the metal-tipped, ram-headed tim ber shatter the bronze-studded panels of the portal. Meanwhile, beyond the limits of the picture, at another sector of the encircling city wall, preparations are under way for a more prolonged siege in case this direct attack fails. The machinery which the Romans could bring against fortified strongholds at tained truly formidable proportions. Engines of considerable variety and great mechanical ingenuity were em ployed. Movable towers of wood, taller than the parapets of the walls, even walls 50 to 60 feet high, were erected of uprights and interlacing timbers on bases carried on huge, solid, wooden wheels. These ungainly structures were trundled close to the walls by the soldiers working under the pro tection of their interlocked shields. The towers carried platforms at sev eral levels, firm enough to support artillery batteries of mechanical slings and still more powerful catapults. From these points of vantage the attackers could clear the parapets un til opportunity offered for lowering from one of the siege towers a wooden drawbridge across which a storming party could swarm to spread left and right along the wall top. More and more troops could be thrown in by this lofty bridgehead until the gate, if not battered in from without, could be opened from inside. Alternatively, the walls could be undermined with tunnels and the re sultant galleries shored up with tim bers. The props of these galleries were then doused with pitch and set afire. With their collapse an entire sector of wall would fall in, leaving an open breach. The sapping trenches were protected by sloping roofs cov ered with earth, wickerwork, hides, or even wet blankets. During the fifth century B. c. the superlative Greek technique of wall building gave a definite advantage to the defensive; but during the next century, in the time of Philip and Alexander of Macedon, the attack began to make good this handicap. Such engineers as Archimedes im proved methods of assault in Hellen istic times; and finally the Romans made such remarkable advances in siegecraft that no adversary could build strongholds impregnable to their well-trained armies. The decline of Roman civilization led to a lamentable lapse in siegecraft during the Middle Ages, so that the advantage shifted back to the de fense. Hence the maze of petty strongholds, chateaux, and castles in which the feudal world shut itself up, until the advent of gunpowder gave attackers again the upper hand.