The film crew stay dry... for now
Most Time Team digs are set firmly on dry land, but when 2000 Roman objects emerged from the River Tees it was time for the Team to get their feet wet. For the next three days you were as likely to see an archaeologist in a wet suit as working in a trench.
For 20 years divers Bob Middlemass and Rolfe Mitchinson had been making discoveries in the river - rings dedicated to Mercury, figurines of Cupid and even what they believed to be the remains of two wooden bridges.
But the invitation to investigate Piercebridge came from one of the British Museum's coin experts Philippa Walton, who was fascinated by the wealth of Roman objects they'd found on the river bed.
Our goal was to work out how 2000 Roman objects came to be on the river bed, whether the two bridges were also Roman and how all that tied together with the history of Piercebridge - an easy three days then.
The first task was to get our heads around the potential 'bridges'. There were two sets of timber strewn across the river bed but could we be sure they were the remains of bridges? And just as importantly, could we work out if they were Roman? Well, the only way to see them was to go snorkelling and the best way to date them was using dendrochronology - using the growth pattern of tree rings to calculate when the tree was felled. So our dating expert Mick Worthington set to work with wetsuit and saw to try and collect a datable piece.
The geophysics team have surveyed some difficult sites over the years, but they've never been asked to walk their equipment across water before. We were attempting an archaeological first by surveying the river bed to look for evidence of the bridge foundations.
Our two Roman bridges next to the modern crossing
A very nervous John Gater watched his precious radar equipment being loaded into an inflatable dinghy and floated across the increasingly rapidly flowing river. The data was collected and carefully processed before being revealed as... inconclusive.
But we weren't just exploring the river - in order to understand the site we had to investigate the wider landscape. To prove that the two lines of wooden posts were bridges we needed to find the roads that once led to them. A relieved geophysics team were then posted onto dry land to survey the north and south banks. On the north side they met with little success, failing to find anything that looked road-like to line up with the western bridge. A series of ditch features did show up and in the hope that one of these might relate to a road, Phil put in a trench.
On the southern bank we had much better luck. Running straight towards our eastern bridge was the line of what seemed to be Dere Street, the main Roman road running from York to Hadrian's Wall. We put in a trench and hit a road surface - this had to be the Roman road and lined up perfectly with John's geophysics.
And the news eventually got better on the other side of the river. Back in Phil's trench, three blistering days of work had uncovered a road and what's more it was leading to the western bridge.
It takes three people to
make sense of the geophysics
So we had two bridges - but how old were they? For two days we collected wood samples for dating, but none produced a result! By Day Three the river levels had risen, making further work in the river impossible. It looked like we wouldn't get the vital date after all... but soon after we left Bob and Rolfe cut another sample and this time a date came back. The western bridge dated to some time between 40 BC and 85 AD, so perhaps this was a prehistoric bridge that was the adopted and maintained by the Romans.
We also confirmed the eastern bridge carried Dere Street across the river. This must have been built along with the road in the late 1st century as part of the big push north. Finally a stone bridge was built, probably at the same time as the big third century Roman fort - the remains of which can still be visited today.
One of the stunning finds from the riverbed
The final task we had set ourselves was to work out why so many finds had found their way onto the river bed and it was the river itself that provided the inspiration for our answer. We were confident that there was a small island in the middle of the river in Roman times and that this could have housed shrines dedicated to the gods in which people placed their offerings. This island was eventually eroded away by the river, leaving all the offerings sitting on the river bed.
After three scorching days of digging and diving we had discovered Roman Piercebridge was twice the size people had thought and had two previously undocumented bridges. Not a bad result but if Bob and Rolfe keep diving here for another 20 years we may yet have to come back!
