Trajan’s Bridge · Drobeta-Turnu Severin and Kostol
By AD 105 the Romans had finished a timber bridge on twenty stone piers, from Drobeta, on today’s Romanian bank, to Pontes, on the Serbian one. The army and its supplies crossed on it. Hadrian took the timber off, and the piers crumbled over the centuries that followed. Today the stumps of those in the river lie under the reservoir of the Iron Gates II dam. We rebuilt the bridge in the real valley, with the Danube lowered to a level from before the dams.
Scroll to cross with the legion.
The gate at Drobeta
The bridge started at the camp of Drobeta. On Trajan’s Column an arched gate stands at its end. Its form comes from the Column; its size is an estimate.
One pier still stands at the Romanian end, in the grounds of the Iron Gates Region Museum. From there to the pier on the Serbian bank at Kostol is 1,074 metres in a straight line.
Over the river
Cassius Dio, a Roman senator writing a century later, marvelled above all at the river:
“...in a river so deep, in water so full of eddies, and on a bottom so muddy...”
Apollodorus of Damascus picked the point where the valley was narrowest. There the current ran even faster.
Twenty piers
“...twenty piers of squared stone one hundred and fifty feet in height above the foundations and sixty in width, and these, standing at a distance of one hundred and seventy feet from one another, are connected by arches.”
A Roman foot was about 30 centimetres. But Dio’s numbers don’t match what the divers found. The 2003 survey, as reported in Ion Šerban’s published abstract, gives piers of 14.7 by 10.2 metres, narrower than Dio’s 60 feet. The model uses those sizes.
At Pontes
On the south bank, in Moesia, the bridge ran into the fort of Pontes, near today’s village of Kostol. Bricks found there carry the stamps of the legions IV Flavia Felix, VII Claudia, V Macedonica and XIII Gemina.
Behind the column lies Dacia. Trajan’s second war against Decebalus began the same year, 105.
What is certain and what is rebuilt
In white is what is known: the two ends of the bridge, how many piers there were, their size as reported from the underwater survey, and the fact that the bridge was timber on stone piers. Only the Column shows that last point.
In orange is what we rebuilt: the exact shape of the arches, the posts, the deck, the parapets, the gates, the ramps. Even the deck height is uncertain. Sources give between about 9 and 19 metres above the water. The model puts it at 15.
Taken apart
Hadrian removes the timber
Trajan’s successor did not want an open road south. Dio writes that Hadrian
“...was afraid that it might also make it easy for the barbarians, once they had overpowered the guard at the bridge, to cross into Moesia, and so he removed the superstructure.”
The year is unknown. The story that Hadrian pulled it down out of envy of Apollodorus does not come from Dio: he records their quarrel, but not in connection with the bridge.
The piers remain
In Dio’s day, about a century later, the piers still stood, with nothing on them:
“...merely the piers are standing, affording no means of crossing, as if they had been erected for the sole purpose of demonstrating that there is nothing which human ingenuity cannot accomplish.”
Marsigli surveys the ruins
Over time the piers crumbled almost to the water. In 1689 Luigi Ferdinando Marsigli, an officer in the Austrian army, surveyed the site and published his plates in 1726. He put the bridge’s length at about 3,010 feet.
A dry summer
In the 19th century, in a summer of very low water, all twenty piers could be seen. The English Wikipedia gives the year as 1858, the Romanian one as 1856. We found no period source, so we give both years.
Around 1875 a travel guide, Murray’s, counted thirteen piers still visible and gave the depth of the water as 18 feet, about 5.5 metres.
Fewer and fewer
In 1906 the Danube Commission destroyed two piers that were in the way of shipping. In 1932 sixteen remained under water. In 1982 archaeologists found only twelve. The river probably took the other four.
Which piers disappeared is not known. So the model keeps all twenty as stumps.
The water
The Iron Gates II reservoir
The Iron Gates II dam, about 68 kilometres downstream, was finished in 1984. The water here rose. In 2002 the water at the Turnu Severin gauge stood on average at 41 metres above sea level. The model uses that as today’s level. We found no reading from before the dam, so we don’t know exactly how much it rose. The model’s 35 metres is an estimate.
The marks on the water show where the piers would lie beneath, if they were evenly spaced.
On the bottom
In 2003 the Serbian Institute for the Protection of Cultural Monuments ran a sonar vessel over the whole site of the bridge, funded by Serbia’s Ministry of Culture. According to reports, it found dressed stone, planks and piles. That survey is where the model’s pier sizes come from.
We found no newer published survey.
What you can see today
Only the two piers on the banks. The Romanian one stands inside a concrete enclosure, built to protect it from the reservoir.
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