What must it have been like to stand and stare out across the edge of the world? From the wall the hills roll away to the horizon, carpeted with a sea of trees, a dark forest that stretches north into a land of barbarians. I can imaging the soldiers brought here from the four corners of the empire, be it Gaul, Macedonia, Turkey, or Africa; what must they have made of the thin ribbon of stone hewn out of the landscape at the edge of civilisation that was now their home.

My tent it pitched for the night in the ruins of Milecastle 39, high in the Northumberland Fells where Hadrian’s Wall runs perched upon the outcropping Whin Sill. Reaching out and touching stones placed 2000 years ago by unknown hands is exciting, the wall itself  still an inspiring presence in the landscape.

I’ve always been fascinated by the engineering genius of the Romans; it’s not just the sheer ambition and scale of their buildings, but also the precision of the construction. Then there is the incorporation of “modern” technologies such as running water for sanitation or hypocausts for central heating, ideas that would be forgotten in the west for almost 1500 years after their civilisation fell.

There is the Pantheon in Rome whose vast dome has stayed standing for almost two millennia with no reinforcement just an exquisite understanding of how forces can be balanced; or the 50m high Pont du Gard aqueduct in the south of France surveyed and built to such accuracy that it falls a mere 2.5 cm in its 300m length.

Hadrian’s Wall even in its prime would never have had the beauty of these structures as it was built to be functional; to keep out, or control the Celts whom the Roman army had been unable, or unwilling to conquer. Today the ruins, ageing softly and gently into the landscape give echoes of its former presence, nowhere better than here where the Roman engineers made use of the cliffs formed by the Whin Sill.

To sleep in a milecastle – unsurprisingly placed every mile on the wall – had been something I’d really wanted to do; a way to link back to a time when there really was an edge of the world and one could stare out over land about which little was known.

Bedding down in Milecaste 39 listening to the wind whip round the tent my mind drifted to thinking about the soldiers who once called this place home. The men were drawn from across the Roman world, from Europe, Africa, and as far east as Syria, brought here to protect this wild part of the empire. What was this place like on a summer day all those years ago, standing on the wall as the sun set beyond the far hills? Did they struggle for warmth on a cold winter night or did a roaring fire banish the chill as the snow beat against the castle walls?

Roman soldiers probably saw more of the world than many of us do in the jet age; the only way here was to walk, from Spain, from Croatia, from somewhere, across the largest empire the world had known. Did they ever stop thinking what was beyond that far horizon, beyond the edge of their world, or did their thought turn back to the long road home?