The central section of Hadrian’s Wall is one of the most remote landscapes in Britain. It is a place of scattered, isolated farms, held by the same families, sometimes perhaps since the time of the Vikings. There is no mobile signal, and few buses, let alone super-fast broadband. The ‘global world’ feels very far away. There is almost no immigration. And it is easy to imagine that the area was even more isolated and traditional in the past: an ancient, subsistence farming economy, with little movement, little sign of man or government.

But 1800 years ago central Cumbria and Northumbria was densely populated, filled with immigrants, drawn from 2 million square miles of Europe and Asia. The land was marked by a succession of vast, contemporary structures, built to a standard specification developed in the Mediterranean. It was powered by a continual flow of manufactured goods from factories in what is now France and Germany. The population fed on food imported from as far away as North Africa. A ceaseless circulation of bureaucrats, generated hundreds of thousands of documents, that moved back and forth along the very latest communication systems. All this is buried within the landscape that we live in today.

When I walked from Newcastle along Hadrian’s Wall, I passed the intersection of the two main Roman roads – now a large roundabout with a pub and gas station – and entered land which was  rougher and apparently more sour. Crops vanished, replaced first with dairy cows, then with suckler cows, and sheep. I followed a section of the wall that ran three stones high over the wet green fellside, across becks, and through gullies. At one point, dozens of horned Swaledale ewes charged past me, scrabbling over the parapet of the wall, pursued by a furious sheep-dog. The collie drove the flock back out of the barbarian lands again into Roman territory, and the sheep leapt, shoved – one somersaulted – panicking over the stone borderline. An old farmer, stood at a distance on a ridge, controlling the dog. He did not pull his crook out of the soil. The wall ran straight through the middle of his pasture, and was no longer even a field boundary. He looked as though he had been in the landscape forever.

The low line of stones, at Birdoswald, on the other side of the gorge from Gilsland, now housed only a single caretaker at night. But eighteen hundred years ago, what was now an open field, containing a dozen Simmental cows, had been occupied by the barrack lines of a vast military camp, occupied by a thousand Dacians. These men were immigrants who came to Birdoswald from a land, three thousand miles away. They were long-limbed redheads with startlingly blue eyes, whose leaders had once worn baggy trousers, and floppy felt hats. Their homeland stretched from modern Romania to the Black Sea: a place for growing fine figs, and olives. Their great capital at home included a sundial twenty feet long, capable of advanced chronological calculations. At home their annual rainfall was 10 inches. They would have struggled to make their sundial work in the Cumbrian rain.

Just as Highland regiments carried bagpipes, so the Dacians carried their ethnic dragon standard – the Draco – which howled when the wind passed through. Just as Highland regiments in the eighteenth century were allowed to wear kilts, after the kilt was banned in Scotland, so the Dacian regiments were allowed to carry their curved weapon in Britain, after it had been banned in Dacia.   They would have brought their own cuisine (just as an African regiment in Roman Scotland carried a casserole dish). They venerated their King Decibalus who killed himself with his fighting sickle, rather than submit to Rome. (You can see a portrait of him, doing it today on Trajan’s column). In the fort of Birdoswald, carved in the Cumbrian sandstone, is a perfect image of the Dacian fighting sickle, to commemorate their building of the granary between 205 and 208 AD; and a tomb of a child, named Decibalus. He had been given the name, at least a century after the last Dacian King Decibalus had killed himself. These were apparently people who believed in tradition.

Later, I clambered over a fence to inspect a deep, broad ditch, with high grass mounds on either side, running straight across a field. A farmer raced up on his quad bike. His family had owned the land on either side of the wall from more generations than he knew. “Hundreds of years, I’d say’. His cows were moving up and down the slopes of the ditch, searching for fresher pasture among rushes and thistles.

“What is it?” he asked. “I heard someone say, it’s an Iron age fortification – built long before the Romans.”

I said that it was the ‘vallum’ defence, built by the Romans at the same time as the wall.

His farmhouse was built from stone, quarried by Roman soldiers. You could still see the marks of their chisels, cutting diagonally across the square stones. Between 120 AD and 410 AD, when the farmer’s ancestors may have been Vikings in Scandinavia, perhaps twelve thousand Romanians lived, worked and worshipped in this now empty field. And their long-limbs lay in the soil around.