By Tom Morrow

The idea of a border wall is nothing new – the concept goes back more than 20 centuries. One of the most famous can still be seen in northern England – it’s named after the Roman emperor who built it.
“Hadrian’s Wall,” also called the “Roman Wall,” or “Picts’ Wall,” was begun in 122 AD as a defensive fortification in the Roman province of Britannia. It ran from the banks of the River Tyne near the North Sea to the Solway Firth on the Irish Sea, and was the northern limit of the Empire.
A significant portion of the wall still stands and can be followed on foot along the adjoining Hadrian’s Wall Path. It is the most popular tourist attraction in Northern England and was designated as a UNESCO World Heritage Site in 1987.
Hadrian’s Wall was probably planned before Emperor Hadrian’s visit to Britain in 122 AD. According to restored sandstone fragments found in Jarrow which date from 118 AD or 119 AD, it was Hadrian’s wish to keep intact the Empire, which had been imposed on him via “divine instruction.” The fragments then announce the building of the wall. It is entirely possible that, on his arrival in Britain in 122 AD, one of the stops on his itinerary was the northern frontier to inspect the progress of the building of the wall.
There were mile castles with two turrets in between. There was a fort about every five Roman miles. From north to south, the wall comprised a ditch, wall, military way and another ditch with adjoining mounds. It is thought the mile castles were staffed with permanent garrisons, whereas the forts had fighting infantry and cavalry. In addition to the wall’s defensive military role, its gates may have been customs posts.

Hadrian’s Wall was 73.0 miles long; its width and height varied according to the construction materials available nearby. East of the River Irthing, the wall was made from squared stone and measured 9.8 feet wide and 16 to 20 ft., high, while west of the river the wall was originally made from turf and measured 20 ft., wide and 11 ft., high, which was later rebuilt in stone. These dimensions do not include the wall’s ditches, berms and forts. The central section measured 7.8 ft., on a 10 ft., base. Some parts of this section of the wall survive to a height of 10 ft.
Sections of Hadrian’s Wall remain along the route, though much has been dismantled over the years to use the stones for various nearby construction projects.
Reasons for the construction of the wall vary, and no recording of an exact explanation survives. Theories have been presented by historians, mostly of an expression of Roman power and Hadrian’s policy of defense before expansion.
Another possible explanation for the wall is the degree of control it would have provided over immigration, smuggling and customs. Limites did not strictly mark the boundaries of the empire. Roman power and influence often extended beyond the walls. People within and beyond the limites travelled through it each day when conducting business, and organized check-points like those offered by Hadrian’s Wall provided good opportunities for taxation. With watch towers only a short distance from gateways in the limites, patrolling legionaries could have kept track of entering and exiting natives and Roman citizens alike, charging customs dues and checking for smuggling.
Construction started in 122 AD and was largely completed in six years. Construction started in the east, between mile castles four and seven, and proceeded westwards, with soldiers from all three of the occupying Roman legions participating in the work.
The wall remains one of the world’s long-lasting man-made edifices. Much like the Great Wall of China. No one is entirely sure why they were built.