Trajan’s Bridge

On the east of the Iron Gate Rapids near the present-day cities of Drobeta-Turnu Severin in Romania and Kladovo in Serbia, there once stood an arch bridge. It was ordered by Roman Emperor Trajan, who led one of the greatest military expansions in Roman history. Under his rule the Roman empire attained the greatest territorial extent stretching from Mauretania in the west to Syria in the east, and Britannia in the north to Egypt in the south. Trajan ordered the bridge to be built so that his legions could cross the Danube and take over Dacia. Consisting of timber arches mounted on masonry piers, the bridge was more than 1,100 meters long, and at the time it was built, it was the longest arch bridge in both total and span length. The bridge stood for only 165 years until it was demolished by Roman Emperor Aurelian when he withdrew from Dacia. Today the only visible remains of the bridge are few of the masonry columns near the bridge’s approach.

Modern day replica of the Trajan’s Bridge. Photo: Carole Raddato/Wikimedia

The kingdom of Dacia, north of the Danube, had been on the Roman agenda since the days of Julius Caesar. The Dacians and the Romans frequently clashed with each other. During one such skirmish in 88 AD, Emperor Domitian was defeated and the Romans were forced to a peace treaty that Trajan considered humiliating. In order to restore the glory of Rome as well as its finances, Trajan resolved on the conquest of Dacia, the capture of the famous Treasure of Decebalus, and control over the Dacian gold mines of Transylvania.

To move his legions faster into Dacia, Trajan ordered a bridge to be built over the Danube. The bridge was completed in just three years between 103 to 105 AD. The structure was 1,135 meters long, 15 meters wide, and 19 meters high, measured from the surface of the river. At each end was a Roman castrum, each built around an entrance, so that crossing the bridge was possible only by walking through the camps. The bridge used wooden arches, each spanning 38 meters, set on twenty masonry pillars made of bricks, mortar, and pozzolana cement.

To built the piers, water was redirected from the construction site, via a tributary. Wooden pillars were driven into the river bed in a rectangular layout, which served as the foundation for the supporting piers, which were coated with clay. The hollow piers were filled with stones held together by mortar, while from the outside they were built around with Roman bricks. The bricks of the piers can still be found around the village of Kostol, retaining the same physical properties that they had 2 millennia ago. The wooden spans were assembled on land and then installed on the pillars.

Trajan’s campaigns against Dacia was a success. At first the Dacians repelled the first attack, but the Romans destroyed the water pipes to the Dacian capital. The city was eventually burned to the ground and Decebalus committed suicide rather than face capture by the Romans. With Dacia’s defeat, Trajan found Decebalus's treasure —a fortune estimated at 165,500 kg of gold and 331,000 kg of silver. The Romans celebrated their victory by holding games for 123 days, with 10,000 gladiators engaging in fights and 11,000 wild animals being killed during that period.

Remains of Trajan’s Bridge. Photo: PANJAVISION/Wikimedia

After Dacia’s conquest, the bridge began to pose as a weak point in the Roman’s defenses. In order to prevent barbarian invasions from the north, Trajan's successor, Hadrian removed the wooden superstructure. The bridge was finally destroyed in 270 AD by Emperor Aurelian. The remaining piers were engulfed by the waters of the Danube, and the bridge was forgotten.

In 1858, the bridge reappeared when the level of the Danube hit a record low due to an extensive drought. It would be another hundred years before an excavation of the bridge was carried out in connection with the Iron Gates Dam construction project. In 1932, there were 16 pillars remaining underwater, but in 1982 only 12 were detected by archaeologists; the other four had probably been swept away by water. Only the entrance pillars are now visible on either bank of the Danube, one in Romania and one in Serbia.

Remains of Trajan’s Bridge. Photo: DjordjeMarkovic/Wikimedia