As early as the Bronze Age, beginning around 4000-3500 B.C., the people of Greece built wooden bridges to cross rivers or wetlands. Bridge builders of this time also laid stone paths through shallow rivers, sometimes making arches of large, overlapping stones through which the water could flow. Stone bridges appeared around 500 B.C. During the Hellenistic* period, from 323 B.C. to 31 B.C., people in northern Greece and Asia Minor built bridges that spanned as much as 1,000 feet. These bridges consisted of stone piers, or supports, holding removable roadways that were made of wooden planks.
The Romans were the greatest bridge builders of the ancient world, just as they were the greatest road builders. In the city of Rome, at least 12 bridges crossed the Tiber River. Elsewhere, engineers traveled with the Roman armies to build bridges so that soldiers could cross the rivers they encountered on their way to battle. Some of these were temporary wooden bridges. Others were pontoon bridges, or floating bridges, of boats placed side by side.
On secondary roads, the Romans built wooden bridges, but for their major roads, they constructed sturdy stone bridges. The earliest known of these was built in 179 B.C. These stone bridges had one or more stone arches that rested on large piers*. The grandest Roman bridges were built somewhat later, at the direction of the Roman emperors. A bridge built under the emperor Augustus to cross the Nera River on the busy Flaminian Way north of Rome had an arch 62 feet high and 100 feet wide. The emperor Trajan commissioned the building of a bridge nearly 3,700 feet long across the Danube River. To span the largest rivers like the Danube, Roman bridge builders used a combination of stone and wood. Piers were constructed of stone and arches were made of wood.
None of the Roman wooden bridges survives today, but some of the stone bridges are still intact. One of the best preserved stone bridges in Italy is the Ponte di Augusto, completed in A.D. 20 at Rimini. In western Spain near Merida, a bridge built by the Romans in A.D. 106 still carries traffic over the Tcigus River. Its six arches rise 245 feet above the river.
* Hellenistic referring to the Greek-influenced culture of the Mediterranean world during the three centuries after Alexander the Great, who died in 323 B.C.
* pier support between two arches or openings