Pons Traiani
About
Apollodorus of Damascus built this bridge across the Danube in just two years, finishing in 105 CE so Trajan's legions could cross freely during the Dacian conquest. Twenty stone piers over 40 meters tall carried wooden arches spanning 1,135 meters in total, the longest bridge built anywhere for a thousand years afterward. It still stood at full length in 117 CE. Hadrian later dismantled its wooden superstructure, but the stone piers endured, and several still break the Danube's surface today.
What happened here
Piers are set on cofferdams — a ring of driven piles, pumped dry, filled with concrete that sets under water. They are built with a cutwater pointing upstream to split the current and the ice. The span above may be stone arches or timber on stone, and timber is not a poor relation: it is cheaper, faster, and replaceable. Roads approach on an embankment so the crossing stays level. Tolls are common, shrines at either end are usual, and the inscription names whoever paid. Floods are the enemy; a bridge is inspected after every big one, and the scour around the piers is packed with rubble. A bridge fixes a town's position for a thousand years, which is why so many are still standing.
In ancient writing
- Cassius Dio, Roman History 68.13
Twenty piers of squared stone carrying arches across the Danube — the work Dio rates above everything else Trajan built, given the depth and the current.
Sources
Roman Maps shows the empire frozen at 11 August 117 CE, the day Trajan died — its moment of greatest territorial extent. Explore the full map →