National Geographic : 1946 Nov
Bridge over the Tiber - . IBER, Father Tiber, to whom the Romans pray," 1 started Rome toward greatness. Until the seventh century B. c. little sea-borne commerce had reached Italy. What trade there was among the villages had been carried on by means of pack animals. Then the Phoenicians, and after them the Greeks, came coasting Italian shores, looking for hides and raw metals, and worked their way up the Tiber to Rome. Open trails in the long river valley tapped resources of the interior communities all the way up to the rugged range of central mountains which shut off the eastern descent to the Adriatic. Thus the little city on the Tiber began to prosper, and under Etruscan rule trade and industry waxed mightily. Rome grew from a group of hamlets into a walled town, from a small trade center into the ruling power of Latium, then Italy, and finally the entire Mediterranean. By im perial times grain ships from Egypt and other parts of North Africa, boats laden with olive oil and wine from Greece and Spain, were discharging their loads at the Tiber wharves and filling the warehouses at Ostia, seaport for the capital. Local transport by raft and barge and rowboat on the river vied with that by road and wagon. Before reaching Rome, 20 miles from the sea, the Tiber, seldom fordable and often in heavy flood, has already run ten times that distance. The early settlement, ringed by the "Servian" Wall, lay wholly on the left bank; and all land communication with Etruria and the country to the north necessitated crossing the stream. To the growth of the city, therefore, bridges were indis pensable. The first spans, their timbers carried onpiles, were easily swept away byfloods, but after theRomans had learned from the Etruscans how tousestone blocks, the wooden structures were replaced by abridge ofstone on rock piers and arches. The modern visitor may still seein the stream close to the bend where theForum communicates with the riverbank a fewshattered remnants ofsuch a bridge, built in 179 B. c. A little farther upstream,pedestrians crossing totheisland sacred to Aesculapius, godofmedicine, move over thearches of another ancient bridge.This, bearing theclearly carved name of its builder, the Road Commissioner Lucius Fabricius, is only one of many structures still enduring towhich the Romans set their hands 2,000 ormore years ago. Throughout the territory that was once the Roman Em pire, arched viaducts maybeseen today. These carried military roads or water channels over gullies and streams and even across great river valleys. The Pont duGard, which brought water to Roman Nemausus onthesiteof present-day Nimes, remains standing insouthern France. North African remnantsoftheoldaqueducts testify that ancient Romans had a greater mastery over theencroaching desert than modern engineers have yet achieved. Caesar's famous bridge across theRhine was atemporary structure for military need. Trajan, however, bridged the Danube with a permanentcrossing nearly three-quarters of a mile long. In Trajan's reign was erected thesuperb Alcantara in western Spain(page 583).