TRAJAN'S BRIDGE

first bridge spanning the Danube River, built east of the Iron Gate Rapids at Turnu Severin by the Roman emperor Trajan (reigned AD 98117) to guarantee the supply line of his legions in conquered Dacia. The engineer, probably Trajan's lieutenant, Apollodorus of Damascus, used timber arches mounted on masonry piers to span the 0.5-mile- (800-metre-) wide river. A century and a half later the emperor Aurelian withdrew from Dacia and demolished the bridge, which is memorialized on Trajan's Column in Rome. Its 170-foot (52-metre) spans were the longest built for more than a thousand years.