A river reveals its Roman past

A 

2,000 years ago the town of Arles, in what is now south-western France, was a busy gateway to the area of the Roman Empire known as Gaul. Goods from all over the Mediterranean were transferred there to barges – long, shallow riverboats – then pulled up the Rhône river to supply the northern half of the great empire. Today, Arles is a small, quiet place, and the Rhône is polluted and mostly ignored.

B 

Archaeologist Luc Long is a native of Arles. He had already worked on sunken ships all over the Mediterranean when, in 1986, a friend persuaded him to dive for the first time in his home river. Long reluctantly agreed. The two men entered the river on a chilly November morning, when the water was around 8°C, thick, cloudy and foul-smelling. They could see no more than a metre ahead through the murky water. At a depth of about six metres, Long saw a sunken truck. To his surprise, he discovered an ancient Roman jar – known as an amphora – on the driver’s seat. These containers were used throughout the Roman Empire to transport olive oil, fish sauce, and other products. When empty, they would simply be discarded. Within a short time the divers found themselves swimming over a vast field of amphorae. Long had never seen so many intact ones, and he has been mapping this Roman rubbish dump ever since.

C 

For the first 20 years or so, no one paid much attention to what Long was doing. When, in 2004, one of his colleagues came across a 34-metre-long Roman barge, Long doubted that there would ever be enough money available to raise it. In 2007, Long handed over the study of this wreck – which he named Arles-Rhône 3 – to three younger archaeologists, and continued his survey of the rest of the dump, around 50 metres upstream. This was where he started finding pieces of the Roman town of Arles, including statues. Word began to leak out. The French customs police warned Long that antiquities thieves might be watching his operation. So when his divers found a two-metre statue of the god Neptune, they brought it to the surface at night.

D 

Before the diving season was over, divers had discovered a rare marble bust of the Roman emperor Julius Caesar. An exhibition was built around the statue, and news of it spread around the world. ‘The exhibition’s success was astonishing,’ said Claude Sintes, director of Arles’ local antiquities museum, where the exhibition was held. ‘When a modest town like ours got 400,000 visitors, the politicians understood that the economic return was strong.’ By the autumn of 2010, the Caesar exhibition was nearing its end, and those same politicians were looking for more culture to invest in, because the European Union had designated the region around Arles a 2013 European Capital of Culture. Suddenly nine million euros became available to build a new wing on the museum and put a Roman barge into it. There was just one small problem. The project would need to be completed by 2013. That meant the barge needed to be extracted by the end of the diving season in 2011. This was because although the wood of the boat had suffered no microbial decay, water had filled its cells, leaving the whole structure soft and spongy. If that were to evaporate, the boat would collapse. The solution was to bathe the wood for months in a polymer called polyethylene glycol, then freeze-dry it in small sections – gradually infusing it with the polymer before extracting the water. The process would take nearly two years.

E 

So there was only one diving season to extract the boat from the Rhône. ‘We thought the project was doomed to fail,’ said Benoît Poinard, a professional diver and the site foreman. Normally, Poinard explained, the Rhône is safe for diving only from late June to October; otherwise the current is too strong. Only three or four months would not be enough to excavate Arles-Rhône 3. Then 2011 arrived. It hardly snowed in the Alps that winter and that spring it barely rained. The Rhône’s current was so gentle that the team got in the water by early May. The team worked straight into November, losing only a single week to bad weather – and completed the job. ‘Two hours after we finished,’ Poinard said, ‘the Rhône became undiveable for the whole winter.’

F 

When Arles-Rhône 3 sank, it was carrying 33 tons of stone for building work. It had come from a quarry just north of Arles, and was probably heading towards a construction site further down the river. The boat was pointed upstream, though, rather than downstream, indicating it had been moored at the quay when it sank. A flash flood had probably swamped it. As soon as the flood subsided, the barge would have been covered in a coating of fine clay no more than 20 cm thick. This was where the archaeologists discovered the personal effects that the crew had left on the boat, including cooking utensils and plates. When the restorers were taking the boat apart, they also found a silver coin sealed between two planks of wood; it had been put there to bring good luck. And it did – 2,000 years later. Arles-Rhône 3 was able to take its place in the new wing of the museum, on schedule, just over two years after re-emerging from the cloudy depths of the Rhône.